I got what you meant GWA
BSOD sorted, took 1 PCI card out at a time till it stopped, damn usb 2.0 card
Still got the blank screen thing tho 
OK. Back to basics!
1. Remove any video card that you've plugged in
2. enter BIOS if enabled, disable 'On-Board' video
3. power on and start in Safe Mode if possible
4. if not enter BIOS and enable 'On-Board' video if disabled
5. power on and start in Safe Mode if possible
6. whilst in Safe Mode enter Device Manager and look for conflicts
After the above you should at least be in a better diagnostic position.
Did you ever install software for the monitor, sometimes they come with a CD. If you did and you can get to Safe Mode, try uninstalling it.
It really is a process of elimination.
And as a final, have you tried another monitor if you are having problems? I had allsorts a few months ago and it turned out to be the Xerox monitor (made in China) that I bought from PC World.