Hi, after installing SP3 on XP, I got a BSOD, and then the computer would not start up, not even in safe mode. It would very quickly flash a BSOD before restarting.

After reseaching on the internet, this seems to be incredibly common, so followed the steps on Microsoft's website to resolve the issue and return back to SP2.
I used the boot up disc, and clicked R to repair. I followed the instructions about typing 'cd $ntservicepackuninstall$\spuninst' and then typing batch spuninst.txt.

The computer did what the microsoft website said it should - messages flickered up about 1 file being copied.
When the 'file being copied' flickering stopped, the prompt came up and I typed exit, as the Microsoft site told me to.

The next step is to start the computer in safe mode to rectify the problem, however my computer will NOT start up in safe mode either.

I have tried it with and without the disc in, but the same happens as when I try to start the computer up normally - a quick BSoD flash, before an automatic restart.

Is there something else I should have typed at the prompt instead of 'exit'?!
Safe mode just keeps restarting and I am stumped. Service Pack 3 is a complete nightmare.

Any help would be incredibly helpful,
Thank you.