Looks like I spoke too soon. Since Ive upgraded Ive gone from never crashing to getting the very occasional BSOD followed by a reboot before I can read the errors. Its rather annoying and SP3 is really the only thing I can blame.

Fingers crossed for some hotfixes.

I think you can turn off the "reboot on BSOD" thing so you can read the errors?

No idea how though!

Right click My Compie > Properties > Advanced tab > Startup and Recovery settings button > untick Automatically restart

Thankee chaps. Its hanging and BSOD on mcdbus.sys, which is something to do with MagicISO. Ill just remove it and see if that fixes it.

but....surely this cant be - issues with XP SP3??....but its XP - and it never goes wrong.....only vista does that.....

Well its working as intended now. I dropped an e-mail to the people at MagicISO so they are aware of it, Im intrigued to know if they are seeing this error since SP3 went live or whether it was just plain bad luck on my part.