You will need an XP Installation CD to try to fix this. If you do not have one, try to borrow one just to run this fix.
Configure your PC to boot from CD if it isn’t already set up that way. You may need to enter the BIOS to configure the PC to boot from the CD.
Set the boot order to
floppy (if present)
SAVE and EXIT
Start your PC with the XP Setup CD in the drive. When you see the “Press any key to boot from CD…” prompt, do so and let the CD-based boot process begin.
When the Recovery Console option is offered (Press R to start the Recovery Console), do so. You may be asked which Windows installation to enter, in which case type the number of the Windows installation you wish to work on (usually 1).
When prompted, enter the Administrator’s password for that Windows installation. If you did not set a password just press ENTER
At the command prompt, type
chkdsk /r (there is a space before the /)