I'm guessing U get a blue screen and U can't get to safe mode. Is that it?
If U CAN get go safe mode then say so!
At the F8 screen ,Disable automatic restart, and you'll see the error next time.
What is the error about? (dll file, sys file, error code)
Do U have an Xp cd? You'll need it to run chkdsk, fix things or do a repair install if U can't get to safe mode.