This occurs because your computer processor detected and reported an unrecoverable hardware error to Windows XP.
The following factors may cause this error message:

- System bus errors
- Memory errors that may include parity or Error Correction Code (ECC) problems
- Cache errors in the processor or hardware
- Translation Lookaside Buffers (TLB) errors in the processor
- Other CPU-vendor specific detected hardware problems
-Vendor-specific detected hardware problems

You can learn from here how to solve this error.