Windows

Run an inplace repair of Windows.

What Bflimfan is telling you to do is insert the Windows CD and run the normal setup routine until you are asked do you want to install Windows or Repair chose the Repair option and run that. It should cure any Registry problems in Windows but it will remove any Patches that you have applied since the install and Service Packs as well. These will be reported as errors and just ignore them and continue with the repair.

While all of your Data will be there when you finish some programs may need to be reinstalled and the unit will have to have any patches/SP's reinstalled.

Take this as a Lesson Backup all of your Data so if you loose a HDD you have not lost all your data or at the very least are up for several K to retrieve the data from a Specialized Data Recovery Company.

Col

Load to your Windows XP diak and go into the recovery console. Once in the recovery console try the folowing commands one at a time and reboot after each.

fixboot

Now reboot and se if that fixed the problem. If it did not go back into the recover console and try the next command.

fixmbr

If that still does not work then do the tasks describe above.

Further to haileyan before you end up doing the reinstall of windows try running chkdsk /p after the reboot from fixboot or fixmbr - it will take forever to check (like about 10 minutes per 1 percent on a 30GB harddrive).