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In this post I am going to write about one way in which you might be able to detect bad sectors.

In this post I am going to write about one experience I have had detecting bad sectors on a hard drive.

In the future I will write other posts about my personal experiences detecting bad sectors.

Below is one experience I have had detecting bad sectors.

I have a friend that I was helping repair his computer over the phone. My friends computer had the windows XP operating system installed.

I had him make a change in the windows registry and then exit the windows registry. I had him go back into the windows registry to make sure that the windows registry had saved our changes. The windows registry did not save our changes. We tried to make the change several times and the windows registry still would not save our changes.

The windows registry is suppose to automatically save changes when you modify anything in it.

The windows registry does not ask you if you want to save changes, it just saves them.

I told my friend to bring his computer to me so I could run a full set of diagnostics on the computer using the PC-Check diagnostic program.

I tested all the hardware in his computer and the only problem detected by PC-Check was that the hard drive had bad sectors. At this point I used a data recovery program to recover his data. After using a data recovery program to recover his data I then used PC-Check to erase all the data on the hard drive and fix the bad sectors on the hard drive.

PC-Check is a good computer hardware diagnostic program that can help you repair bad sectors on your hard drive. PC-Check does not have a bad sector repair option in it’s menus but the way to repair bad sectors with PC-Check is to use the option that erases all the data on the hard drive you want to remove the bad sectors from. This option is usually the Low Level Format, Destructive Write Test or Low Level Initialise Drive option. This option may be called something different in each version of PC-Check.

The point I am trying to make is that when you try to make a change to the windows registry and the windows registry will not save your changes then one possible reason might be that the hard drive has one or more bad sectors. Of course any time that you try to make a change to the windows registry and the windows registry will not save your changes this does not always mean that your hard drive has one or more bad sectors. You will need to check the hard drive to see if it does have any bad sectors.

Also if you are having trouble opening some files or saving some files on your hard drive then one possible reason could be that your hard drive has one or more bad sectors. If you are having trouble opening or saving some files you might see an error message when you try to open or save certain files. Of course your hard drive might not have any bad sectors when you are having trouble opening or saving some files. You will need to check the hard drive to see if it does have any bad sectors.

For a list or programs that can detect and repair bad sectors read our Data Recovery From Bad Sectors post.

For free data recovery software read our Free Data Recovery Software post.

For even more data recovery programs read our Data Recovery Software Experiences post

In this post I am going to write about how data recovery undelete software and data recovery undelete programs work in the MS-DOS operating system.

In this post I am also going to write about how data recovery undelete software and data recovery undelete programs work in any Windows operating system.

First I am going to write about how data recovery undelete software and data recovery undelete programs work in the MS-DOS operating system.

The MS-DOS operating system uses the Fat(File Allocation Table) file system.

When a file is deleted in MS-DOS the first character of the file name is replaced with E5 hex. The E5 hex lets the MS-DOS operating system know that the file is deleted and the space used on the disk is ready to be overwritten by another file.

The space for the deleted file may not be overwritten right away. Until the space for the deleted file is overwritten you can use an undelete program or any undelete software to undelete and recover the file.

When the file is deleted and the first character of the file is replaced with E5 hex the only other information for the file that is changed on the disk is the Fat(File Allocation Table) entries. The Fat(File Allocation Table) entries are cleared and set to 00 hex.

All of the other information about the file on the disk is unchanged. The directory entry for the file is still there on the disk unchanged with the exception of the first character of the file name being changed to E5 hex and the data that was stored in the file is still on the disk.

All a data recovery undelete software or data recovery undelete program needs to do to undelete the file is replace the first character of the file name which is E5 hex with any valid character for a file name and rebuild the Fat(File Allocation Table) entries for the file.

Some undelete programs will replace this E5 hex with whatever character they want and let you know what the name of the undeleted file is. Some undelete software will ask you to type the character that you would like to use as the first character of the file name.

When E5 hex is replaced with a valid character and the Fat(File Allocation Table) entries for the file are rebuilt then the file is undeleted.

After you have deleted a file in MS-DOS that you would like to recover it is very important that you try to recover the file right away before any data is written to the disk that the file was deleted from.

Two reasons the data could be overwritten when using MS-DOS is below.

Using the defrag built into MS-DOS or any defrag program can destroy the information for the deleted file and make recovery impossible.

Also if you install any program in the MS-DOS operating system or copy any files to the disk MS-DOS is installed on this could overwrite data that you want to undelete or recovery. This assumes that the data you want to undelete was deleted from the drive or partition that MS-DOS was installed on.

Now I am going to write about how data recovery undelete software and data recovery undelete programs work in any Windows operating system.

The Windows operating system can use either the Fat(File Allocation Table) file system or the NTFS (New Technology File System).

Most of the information in this post assumes your windows operating system use the Fat(File Allocation Table) file system. Some of the information below can still be useful if your windows operating system uses the NTFS(New Technology File System).

Any windows operating system from the windows 95 operating system to the current Windows 7 operating system support using long file names.

If you are using any windows operating system that supports long file names then undeleting a file is somewhat different than it is in MS-DOS.

The undelete program would still have to replace the first character of the file name which would be E5 hex for a deleted file with a valid character for the file name and rebuild the Fat(File Allocation Table) entries for the file just like I wrote about above when undeleting a file in MS-DOS. This part of undeleting a file is the same thing you do when undeleting a file in the MS-DOS operating system.

The one thing that is different when a file with a long file name is deleted in an operating system that supports long file names is below.

The directory entries for the long file name are changed to E5 hex.

You can see this change if you look at the long file name information with a disk editor before and after it is deleted.

Any undelete software you use will have to be programmed with long file name support to undelete the file with long file names properly.

Long file names have been around a long time so any undelete or data recovery software should be able to handle long file names properly.

After you have deleted a file in any Windows operating that you would like to recover it is very important that you try to recover the file right away before any data is written to the disk that the file was deleted from.

Any data written to the disk could overwrite the data for the file that you want to undelete.

The information below about how data might be overwritten when using any windows operating system can be useful when your windows operating system is using the Fat(File Allocation Table) file system or the NTFS(New Technology File System).

Some reasons are below that data might be written to the disk if you are using any windows operating system.

Windows update might be enabled on your windows operating system. If it is enabled it could download updates to your computer and also install those updates. Downloading the updates to your computer or installing the updates on your computer could overwrite the information on the disk for the file you want to undelete and recover.

Also If you are using a web browser to go download an undelete data recovery program then you should probably do this from a different computer than the one that you want to undelete and recover your file from.

The reason for this is because Internet Explorer and all web browsers save files to your disk when you are going to different websites. Sometimes the data is cookies. Sometimes the data is cache files. Also I think that internet explorer changes the windows registry to include the url of the websites you are visiting. Doing any of this can overwrite the data you want to undelete and recovery.

Using windows defrag or any defrag program can destroy the information for the deleted file and make recovery impossible.

By default defrag is set to run on a schedule once a week in windows vista and windows 7 when the computer is on but idle.

Also if you install any programs in the Windows operating system or copy any files to the disk Windows is installed on this could overwrite data that you want to undelete or recover. This assumes that the data you want recovered was on the same disk or partition that windows is installed on.

The point I am trying to make is that data is written to the disk in the background all the time in windows operating systems and you need to undelete the file as soon as possible so that the data for the file is not overwritten.

Even if you install undelete programs or data recovery programs on a different drive than what windows is installed on you will still overwrtie some data on the drive windows is installed on because programs that are installed in windows usually write to the windows registry which is on the drive windows is installed on.

If you need to undelete or recover data in the windows operating system and you don’t have any programs already installed on your computer to do this I suggest that you use portable undelete and data recovery programs because these don’t need to be installed and will not modify the registry of the windows boot drive.

If the data for the file you want to undelete is overwritten you will not be able to recover the file.

For information on undeletion see the Wikipedia Undeletion article

In this post I am going to write about the speed of hard drive controllers as it relates to data recovery.

I have noticed from my own experience that if you are using a data recovery software program in dos then the speed at which the hard drive can be scanned and recovered will be much faster if the hard drive you want recovered is plugged into a good quality PCI or PCI-Express hard drive controller card instead of being plugged into one of the hard drive controllers on the motherboard.

This also includes data recovery programs that boot your computer from a CD without dos loaded. I have used data recovery programs that boot your computer from a CD without dos loaded and these data recovery programs have been faster at data recovery when the hard drive I wanted recovered was plugged into a hard drive controller built into a PCI or PCI-Express hard drive controller card instead of being plugged into one of the hard drive controllers built into the motherboard.

I think the reason for this is because the hard drive controllers on some PCI and PCI-Express hard drive controller cards are much faster than some of the hard drive controllers built into some motherboards. The reason could also be that you have a motherboard with older hard drive controllers built into it.

This is also true of data recovery programs run in the windows operating system. From my own experience data recovery programs run in the windows operating system will be able to scan and recover the files from the hard drive faster if the hard drive is plugged into a good quality PCI or PCI-Express hard drive controller card instead of being plugged into one of the hard drive controllers built into your motherboard.

One other thing I have noticed is that a data recovery program used in the windows operating system should be able to scan and recover a hard drive faster than a data recovery program used in dos even if the hard drive you want to recover is plugged into one of the built in hard drive controllers on the motherboard. If the hard drive is plugged into a good quality PCI or PCI-Express hard drive controller card then the data recovery program for windows will be able to recover the hard drive faster than if the hard drive were plugged into one of the built in hard drive controllers on the motherboard.

Every PCI or PCI-Express hard drive controller card may not have faster hard drive controllers on it than the hard drive controllers built into your motherboard but for me I have noticed a good speed increase when using data recovery programs to recover data on hard drives that were plugged into any hard drive controllers on a PCI or PCI-Express hard drive controller card I have bought from Promise Technology.

Below is a link to the website for Promise Technology.

1.Promise Technology

I have always bought my PCI and PCI-Express cards from promise technology. If you know of any good company’s that offer good quality PCI and PCI-Express hard drive controller cards then leave a comment to let us and our blog readers know.

I have used Promise Technology hard drive controller cards for years and have had no problems with them.

If you have any other thoughts on this subject please leave a comment to this post.

For more information on hard disk controllers read the disk controller wikipedia article.

For information on How IDE Controllers Work see the HowStuffWorks.com How IDE Controllers Work article.

Below is a free data recovery program that I have used in the past to recover some of my files. If you need your data recovered then you should try the data recovery program below to see if it can recovery your files.

1.PC INSPECTOR™ File Recovery

If PC INSPECTOR™ File Recovery cannot recover your data then this does not mean that your data cannot be recovered. As i said before you need to run multiple data recovery programs to try and recover your data. One data recovery program may be able to recover some of your data or may not be able to recover any of your data at all and another data recovery program might be able to recover all of your data.

This can happen because of data corruption on the disk. For more information on data corruption on the disk read our Data Recovery and Corrupted files post.

If you would like to learn more about the structures on the disk then read our Learning Data Recovery post. Learning about the structures on the disk and how the file system stores data can help in finding data corruption in the structures on the disk and correcting them.

To correct the structures on the disk you need to use a disk editor. For information on disk editors read our Data Recovery and Disk Sector Editors post.

If you know of any good free data recovery software then leave a comment to this post to let our blog readers know about it.

Below are some good disk editors for windows and linux.

1.DiskExplorer for NTFS

2.DiskExplorer for FAT

3.DiskExplorer for Linux

4.Disk Digger

Below is a full data recovery program that has a disk editor built into it.

1.Media Tools Professional

Media Tools Professional will need a windows system to create the CD that it boots from to run. Once the CD is created in windows then Media Tools Professional can run without windows being started.

Below is a good free hex and disk editor for windows.

1.HxD – Freeware Hex Editor and Disk Editor

These disk sector editors could help you if you understand the disk structures and are trying to recover a file manually because none of the data recovery programs you are using are able to recover your file.

Also if you are a programmer then you could use the disk editors above to make sure that any data recovery programs you make work. For example if you are making a data recovery program that is able to repair the boot sector of a disk then you could use a disk sector editor to erase the boot sector of the disk you want to try and repair with your data recovery program to see if your data recovery program can repair the boot sector on the disk properly.

For more information on disk editors read the disk editor wikipedia atricle.

For more information on disk structures read our Learning Data Recovery post.

If you know of any good disk editors please leave a comment to this post and let our blog visitors know about them.

We have to have this code here for technorati tags RFEBUED6TYTK

If you want to recover your data before repairing any bad sectors then I suggest you use a program that can read a bad sector more than once to increase your chance of being able to get a good read on a bad sector. This would give you a good chance at recovering your data from the bad sector. You might not always be able to recover all the data from the bad sector so I suggest that when your data is recovered that you check and make sure all of it is there.

One such program that can read a sector more than once is.

1. Media Tools Professional

When you need to recover data from bad sectors then the program below is one of the better programs to use on a hard drive with bad sectors. If the bad sector cannot be repaired then data is moved from the bad sector to a good sector.

1.SpinRite

Also if you want to try and repair the drive with bad sectors without erasing all the data on the hard drive then spinrite is one such program that can do this.

PC-Check is a good computer hardware diagnostic program that can help you repair bad sectors on your hard drive.

PC-Check does not have a bad sector repair option in it’s menus but the way to repair bad sectors with PC-Check is to use the option that erases all the data on the hard drive you want to remove the bad sectors from.

This option is usually the Low Level Format, Destructive Write Test or Low Level Initialise Drive option. The option you choose in PC-Check will be the option to erase all data on the hard drive with bad sectors. This option may be called something different in each version of PC-Check.

Make sure to use a data recovery program first to recover any data you want off of the drive before using PC-Check to erase it.

PC-Check may not always be able to remove the bad sectors from the hard drive so this may not always work.

One reason that PC-Check may not be able to remove bad sectors from a hard drive by erasing it is because over time the magnetic media on the hard drive can become weaker. A hard drive comes with spare sectors that are used in place of the bad sectors when needed. When there are no spare sectors left on the hard drive then any other bad sectors that the hard drive gets cannot be repaired.

Also if you are interested in a good hardware diagnostic program to check all the hardware in your computer for problems then PC-Check in my opinion is the best program to use for doing this.

Get more info on PC-Check

If you have tried using PC-Check or some other diagnostic program to Low Level Format your hard drive and still have bad sectors then I have one more bit of information to tell you that might help.

We have read that using the following program below may be able to help repair bad sectors that a Low Level Format may not be able to repair.

1. HDD Regenerator

Also if you want to try and repair the drive with bad sectors without erasing all the data on the hard drive then HDD Regenerator is another program that can do this.

For more information on bad sectors see Wikipedia Bad Sector article

For even more information on Bad Sectors read Hard Disk Drive Myths Debunked

If you have used programs that have been able to repair bad sectors on a hard drive for you then let us know which programs you have used.  I am sure our blog readers would be interested in that information.

I have used the following program below to recover data from one of my music CDs.

1. Exact Audio Copy

The music cd that I used Exact Audio Copy to recover was scratched and the audio was skipping like crazy when played. Once I used Exact Audio copy then the music played almost perfectly with very little skipping. If you have a music CD that skips when played then you should give Exact Audio Copy a try. It might be able to save the songs on your CD.

Exact Audio Copy is a free program.

I have used the following programs below to recover data from CD, CD-R and CD-RW discs. These programs will also recover data from DVD discs.

1. CD/DVD Diagnostic 3.0

2. DVD Data Rescue® v3.0

3. CD Data Rescue® v2.6

4. isobuster

5. CDRoller

One time I had a CD-RW disc that I used to store files on using InCD from the NERO Burning ROM program. My system crashed and had to be reinstalled. When I installed the newer version of NERO  that had a newer version of InCD I could not access the files on my CD-RW because the CD-RW disc had not been closed out. I did not want to reinstall the old version of NERO Burning ROM  just to access my files on the CD-RW disc. I used CD/DVD Diagnostic to recover all my files off of the CD-RW disc and it recovered every single file without any problems. Out of all the programs I tried to use to recover the files from my CD-RW disc CD/DVD Diagnostic was the only one that was able to read and recover the files from my CD-RW disc.

For information on How CDs Work look at the following article from http://www.howstuffworks.com title How CDs Work.

For more information of CD-R discs view the CD-R information on Wikipedia

For more information of CD-RW discs view the CD-RW information on Wikipedia

For more information of DVD discs view the DVD information on Wikipedia

I suggest you search the HowStuffWorks website for more info about CD, CD-R,CD-RW and DVD discs.

When you are using a data recovery program to recover your files you need to make sure that the files recovered are not corrupted. Some data recovery programs will tell you that the data is not corrupted before recovery but the best way to check for data corruption is to

1. If its a document then open the document and see if all your data is there. If the document is corrupted then the document will not open or the document will open but some of your data will be missing.

2. If its a program then see if the program will start. If the program is corrupted then it will not start or run properly.

3. If its a picture then open the picture in a program and see if the picture opens.

Even if the data recovery program your using to recover your files tells you that the data that you want to recover is not corrupted before you try and recover it you still need to check the recovered data for corruption after recovery. The data could be corrupted even if the data recovery program tells you your data is not corrupted.

One reason your recovered data might be corrupted is that some data recovery programs use the boot sector, partition table and Fat(File allocation table) on the disk to recover your files. If the boot sector, partition table, or Fat (File allocation table) information on the disk is corrupted then the recovered data will be corrupted.

This is one reason that using a data recovery program that does not need to look at the boot sector, partition table or Fat (File allocation table) on the disk could recover your data in the case where the boot sector, partition or Fat (File allocation table) on the disk is corrupted.

Read more information on The PC Guide about the Fat(File allocation table)

Read more information on Wikipedia  about the Fat(File allocation table)

We have mentioned the Fat (File allocation table) in this post. There is another file system called NTFS (New Technology File system)

Read information on the PC Guide about the NTFS(New Technology File System)

Read information on Wikipedia about the NTFS(New Technology File System)

For more NTFS(New Technology File System) information we suggest you visit http://www.ntfs.com/

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