Hi again,
I'm sorry that I seem to have only partially listened to your last post (it's no excuse but i'm involved in lots of posts at the same time)
It seems to me that it's a graphics card issue. Since you seem very well versed in hardware - I want you to try this route first. Can you safely shut down the pc and follow all safety precations that you normally would prior to opening up the box. I want you to remove and reseat the graphics card for me. As you are here anyway, i'd like you reseat all hardware components that are reseatable (ie not fixed components)
This may seem like i'm questioning your previous install steps but this is not the case - these things can become loose, it's a fact of life. If you do this and you find the same issues - I want you to consider a possible software problem which may require a re-install, I know this seems drastic, but it may be that due to previous install problems for the graphics card software we have an issue that is unrecoverable without a reinstall - but that's in the future and ONLY AS A LAST RESORT, I only want to prepare you for this eventauality (the reason this is SUCH AN ISSUE FOR ME IS THAT YOU CANNOT BACK UP AT THIS POINT AS YOU CANNOT SEE YOUR SYSTEM TO BACK IT UP)
Before any of these drastic measures I would recommend unplugging all devices and restarting your machine again. (**this is to eliminate conflicts - THESE ARE COMMON - eg you could find that your printer drivers prevent your new graphics drivers from running)
An additional thought here - do you have a spare VDU that you can replace? - It would just narrow the issue for troubleshooting purposes. Don't worry if not (i don't think this is the issue, but you never know!)
You maybe able to save time in the long run by (temporarily) changing the graphics card - I think this is the route of your issues (not the card itself but the software that it's trying to use to access it)
Try my steps - let me know how it went
Good luck - Wish you well
Steve