XP System Restore & Recovery console

System restore: In some cases, a reinstallation can be avoided by using system restore. If you are unable to get system restore to work from within safe mode, you can try to access it from within a command prompt. You do not need to leave safe mode to do this, just follow these instructions closely:
1.Reboot into safe mode with a command prompt.
2.Get to an administrator account so that you have the needed permissions to get things done.
3.At the command prompt, type: %systemroot%\system32 restore strui.exe
4.Follow the instructions to restore your PC to an earlier state of operation.

Recovery console: The XP recovery console can be a very useful utility when employed with care. There are a variety of situations where having access to it can be really handy. In fact, you need to get access to it before we go any further.
1.Reboot from the Windows XP CD. Once you arrive at the welcome screen, choose "R" for recovery.
2.You will be asked which Windows installation you wish to access. Choose the appropriate number.
3.Now a prompt for your administrator password will appear. Enter it and continue (if no password, press enter).

Now we are ready to roll up our sleeves and get to work. While at the console, you can type help for a list of available commands that are at your disposal. For example, you can repair a messed up boot sector by typing FIXBOOT and then typing enter afterward. If you are having difficulty booting up because of a messed up ntldr file, however, then you might need to replace it by typing:
copy e:\i386\ntldr c:\
copy e:\i386\ntdetect.com c:\
(Keep in mind this is assuming that E: is the correct drive letter for your CD ROM drive). Once you have repaired what you have needed to from the recovery console, simply type EXIT at the prompt to leave and restart Windows.