Hold the Flag key down and tap R key, type the following into the run box     sfc /scannow

 

space between    c    and      /  

 

Hit enter, it may ask for your XP CD, put it in the CD drive if it does, let it run to completion, there will be no notification when it is done except the window will close. Reboot the PC and see if anything changes for the better.

 

Now do a windows update if all is well.