Corrupted Windows XP registry settings can cause XP to be unable to boot up as well as other issues. If you are unable to boot up Windows and desperately need to access precious data files in your hard disk, you can try to repair Windows XP registry settings.

Basically, there are 2 ways to do so. The first method is to use the XP CD/DVD to boot up and repair your Windows installation. The CD/DVD is usually provided by the vendor when you purchase the PC or laptop. Do not confuse this with the recovery disk. A recovery disk will reformat everything in your hard disk and erase all data, restoring the PC or laptop to the state when it is delivered. This is not what you want.

Insert the XP CD/DVD into the DVD drive and power up your PC or laptop. When you come across a prompt asking you to "Press any key to boot from CD", press the space bar or any keys. A blue screen will appear and the system will be copying some files. Once it is done, you will be asked to install XP or Repair Windows using recovery console, press "Enter" to install XP and then press F8 when you see the user agreement. When you see your Windows installation in the next screen, press 'R' to start the repair. After that, just follow the instructions given and you should have a running XP in no time. You might need the XP CD key for this repair so be sure to get it ready. It can be found either in the XP CD/DVD sleeve or on a sticker on your PC/laptop. You should repair Windows XP registry settings with this method only when you cannot start Windows at all.

The 2nd method which is far easier is to use a registry cleaner. It will remove any invalid entries and resolve corrupted entries in Windows XP registry settings just with a few mouse clicks. You should use this tool if you are able to at least boot up to Windows. It is far more hassle free. You simply need to do a registry scan with the cleaner and the software will show you a list of issues found and then you can choose whether to fix them all or individually.