If it's a damaged file system case then:-
1.Insert the Windows XP CD-ROM into the CD-ROM drive, and then restart the computer.
Click to select any options that are required to start the computer from the CD-ROM drive if you are prompted.
2.When the "Welcome to Setup" screen appears, press R to start the Recovery Console.
3.If you have a dual-boot or multiple-boot computer, select the installation that you must access from the Recovery Console.
4.When you are prompted, type the Administrator password. If the administrator password is blank, just press ENTER.
5.At the command prompt, type chkdsk /r , and then press ENTER.
6.At the command prompt, type exit , and then press ENTER to restart your computer.
This takes a bit longer, but the system should boot back into Windows.
