Thanks for your help guys, no I didn't get to see BSOD for long enough, and now I can't!
I had one windows update a few days back, and I had installed software for Pinnacle Showcenter (PS) the day before crash, but was able to remove during one Safemode bootup. I also turned on my wireless facility to connect with the PS, but was also able to reverse during above safemode.
Will try and disconnect slave HDD, and also see if I can get a spare video/graphics card to try....will have to wait after Easter hols.
Can just slot this into the PC, and it will use this instead?