This is RAM error,



change the ram,
or
sometimes depending on how far it will boot and what version of windows it is. You can hit the F8 key as it is first starting up and get into safe mode. From there you can get into "My Computer" and right click on the "c" select the tools tab and do a defrag and schedule a disk check - check both boxes in disk check - one says "check for errors" the other one say "attempt to repair" This will fix it about 60% of the time!!! Good Luck!!!!

If you are not comfortable, unplugging and re-installing hardware in your PC, this may be a good time to have a technician look at it.
However, if you have ruled out a hardware issue, then you will need to start up your PC in safe mode. The first thing you should try in safe mode is a virus check and spyware scan of your entire system. If anything was found, eliminated the problem then try to restart Windows XP again in normal mode.
If nothing showed up on the scans, then boot up again in safe mode and use the built in system restore utility. When running your system in safe mode, you can still access all the recent restore points created by the system restore utility. Run your system from the last known ‘good configuration’. On the other hand, if you know a recent software installation is the cause, then restore to the point created at that date.

EDIT: My suggestion is to switch to windows se7en, it wont dump ur ram.