Your computer system files are corrupted.

If your data is not backed up REFRAIN FROM WRITING ANYTHING ON THE HARD DRIVE. Doing that might overwrite your data. Do not play with FDISK or other such utilities as these automatically write on your hard drive as soon as you launch them! Windows XP makes copies of your Master Boot Record and Master File Table. We are going to attempt to recover these files.

This time we are going to use a data recovery software to attempt to recover and repair your partition and file tables. We're going to the data recovery page, and we'll use the free software there to repair your tables.

Go to Data recovery.

If you do not have anything special on your PC that you want to recover, then you might also consider re-installing your Windows XP. It is the safest solution and the best long term choice.

Go to Windows XP install.