Guide : How to Fix a Corrupt Windows File System

Many Windows systems become corrupt for a variety of reasons, and this leaves you between a rock and hard place in which you want to throw the computer away. But, luckily, there are many ways to work around and fix problems that can occur. This guide can fix a variety of errors and problems with Windows, which can include but is not limited to :
- Error Dialog Boxes
- Startup Failures
- BSoD's, (Blue Screen of Deaths)
- Windows Applications not functioning properly

CheckDisk

CheckDisk comes with Windows as standard, and is the default utility to scan and fix file system and harddrive errors. Although not full proof, it has proven to be a very resourceful and useful tool. This is usually a good place to start when trying to fix corrupt Windows files, as it could be the cause of the corruption, and fixing it is the priority to prevent further problems. 

To run CheckDisk, you need to open a Command Prompt. 

In Windows XP : Click on Start->Run. Then, type in the box, cmd.exe. The Command Prompt will open.

In Windows Vista/7 : Click on Start, and then type cmd in the search box. Then, on the found file, cmd.exe, Right-click, and choose Run as Admin. 

After you have opened the Command Prompt, you can run CheckDisk. Do so, by typing in chkdsk /r. The /r option tells CheckDisk to automatically attempt to repair corrupt sectors on the drive. (You can use /f as well, which also repairs file automatically) Usually, when running the utility directly will result in an error, as shown to the right.

Simply type Y when it prompts to scan at restart, and then restart your computer. A scan will then start before entering Windows after a reboot. 

When the system was checked and errors fixed, then you can move on to the next steps in fixing corrupt files.

System File Checker

The System File Checker is designed to check files installed on your drive, and compare them to what they are supposed to be. Any file that is not the same is then re-copied from the Installation CD (which you will require to use this utility). This fixes many corrupt file problems, and is highly recommended to solve errors and non-functioning or malfunctioning Windows applications.

To run System File Checker, you need to open a Command Prompt again. Same as above.

In Windows XP : Click on Start->Run. Then, type in the box, cmd.exe. The Command Prompt will open.

In Windows Vista/7 : Click on Start, and then type cmd in the search box. Then, on the found file, cmd.exe, Right-click, and choose Run as Admin. 

Insert your Windows Installation Disc. This must be the same version as the one installed, or it might not work. Then, in the Command Prompt box, type 

sfc /scannow. This will initiate and run the utility. This may take a while, so be patient. 

If no errors are found using the System File Checker, or if it doesn't solve the problem, there is another way to fix corrupt files. 

Repair Install

A repair install basically reinstalls Windows, overwriting files on the drive, but only reinstalling Windows core operating system files and drivers. This method keeps documents, applications, profiles and most of the other settings intact. 

For instructions on how to perform a Repair Install on Windows XP, check the guide How to do a Repair Install on Windows XP

I will have a link up for how to perform a Repair Install on Windows Vista or 7 soon. 

If none of these 3 base options work, there is a good chance that your system is corrupted pretty badly, which is usually caused by malware and virusses. If this is the case, the last resort is to format the drive, and reinstall a clean installation of Windows onto it. This is usualy undesirable, as it deletes all user files and documents, but if the system is too unstable to fix normally, it is the most effective way to deal with it.

I will post up a guide on how to do a clean install at a later date, and link it here. 

Any questions or comments can be posted here if you need help with corrupt system files.

Guide : How to do a Repair Install on Windows XP

Windows XP has its faults, and sometimes software, device drivers or any other outside interference can cause corruption in the files systems of Windows, rendering it unusable or unstable. To fix this, there are many methods, but one final fix is to do a repair install.

A Windows Repair Install reinstalls Windows over the installation already present on your computer, but does not delete user data, preferences or other information that is not system based. It simply replaces all system files, and thus fixes many corruption errors. This is a safe way to fix a broken OS without actually having to start all over again user-data-wise.

Now, on to the how to :

Step 1

Check that your Windows XP CD is the same version as the one you have installed. You cannot repair install a XP Home installation using a XP Pro disc. 

Place the disc in your drive, and make sure in the CMOS settings that you boot from the CD-/DVD-ROM first. 

After POST and bootup, you will see a message, "Press any key to boot from CD". Then, as suggested, press any key, and Windows Setup will load.

Step 2

After Setup loads system files necessary for the installation, you will end up on the start screen. From here, choose to set up Windows by pressing Enter. After this, you should press F8 to agree to the Terms and Conditions.

Note : This make take some time depending on the system, and files that setup requires for your computer.

Step 3

Setup will scan your computer for existing Windows installations. Then, it will list any installations found. If you want to install a fresh copy of Windows (deleting the previous installation), you press ESC. But, we want to do a repair install, so we will select the appropriate OS found on the system and type "R".

Note : If there are no installations shown here, or if the option for repair isn't available, it means that the Win XP version in your CD drive isn't the same as the one that is installed. You cannot perform a repair install if this is the case.

Step 4

From this point onwards, the installation will continue like a normal install, except for the setting up of user settings screens later on. They are skipped because the info is already on the previous installation. You will need to retype your CD-Key. After everything has finished, your desktop will load like normal, and the Repair Install has been completed.

Note : Whether this has fixed your problem or not will still have to be tested. If a problem persists, additional troubleshooting will be required.

If there's any questions about the repair install on Windows XP, please do not hesitate to post them in the comments and I'll give you an answer.