Without any form of macine spec/description or any details about the BlueScreen message any answer would be wild guess...
Wild Guess causes could be:
RAM problems: run memtest86 (or similar),
BIOS not configured correctly: (RTFM),
Trying to install XP on a current SATA based MoBo (without using the drivers disk) and expecting it to just work (RTFM again).
If you want a more targeted reply, try posting some details...