I suggest that you try running a chkdsk from your install disk.
Follow these steps:
•When you turn on your computer, watch your computer screen for a Boot Option key. If one is not available, use the key for Setup.
•You want to boot from your install disk. If you were able to get the Boot Option screen, select the CD drive. If you had to go to the Setup screen, set the CD to be the first boot device.
•Put your Windows XP CD in your DVD/CD Rom and start your computer.
•When you get this message - Press any key to boot from CD, press the Enter key (or any other key) on your keyboard.
•Let your Setup begin, do not press anything.
•When you receive the message to press R to repair Windows by using the Recovery Console, press the R key.
•Select the Windows installation that you want (it's usually 1), and then type the administrator password when prompted. If you don't have a password, just press the Enter key.
•At the recovery console command prompt, type the following command, and then press the Enter key:
CHKDSK /r
Chkdsk will run and look for hard drive problem. It may take 30 minutes to a few hours depending on the size of your hard drive.
When chkdsk is finished, remove the install disk and restart your computer.