Quote:
Causes:
Bug check 0x50 usually occurs after the installation of faulty hardware or in the event of failure of installed hardware (usually related to defective RAM, be it main memory, L2 RAM cache, or video RAM).
Another common cause is the installation of a faulty system service.
Antivirus software can also trigger this error, as can a corrupted NTFS volume.
Resolve:
Resolving a faulty hardware problem: If hardware has been added to the system recently, remove it to see if the error recurs. If existing hardware has failed, remove or replace the faulty component. You should run hardware diagnostics supplied by the system manufacturer. For details on these procedures, see the owner’s manual for your computer.
Resolving a faulty system service problem: Disable the service and confirm that this resolves the error. If so, contact the manufacturer of the system service about a possible update. If the error occurs during system startup, restart your computer, and press F8 at the character-mode menu that displays the operating system choices. At the resulting Windows Advanced Options menu, choose the Last Known Good Configuration option. This option is most effective when only one driver or service is added at a time.
Resolving an antivirus software problem: Disable the program and confirm that this resolves the error. If it does, contact the manufacturer of the program about a possible update.
Resolving a corrupted NTFS volume problem: Run Chkdsk /f /r to detect and repair disk errors. You must restart the system before the disk scan begins on a system partition. If the hard disk is SCSI, check for problems between the SCSI controller and the disk.
Finally, check the System Log in Event Viewer for additional error messages that might help pinpoint the device or driver that is causing the error. Disabling memory caching of the BIOS might also resolve it.
Since you're running XP, you could start off by trying a System Restore.