Yeah, I called the card manufacturer to ask about the nVidia/Vista conflict and how to solve the driver problem with a new build that would not allow access to any video.
They were instantly adamant that there is no conflict with the cards, but that Vista will not install with over 3gb, so I have to reduce from 4 x 2gb sticks to 1 x 2gb stick, install Vista then refit the extra ram again.
They swear it will solve the problem. Possibly aggravated that it's 64 bit, so not quite so common on the forums when researching faults.
I sat and watched Vista load, all the opening screens are there (with digital video) as it asks the setup questions and "gathers information", then it unpacked 100% of files, and set itself nicely, tick/check marks at each of last three "stages" then black. I did see occassional blue screens/white text warning of "critical windows error" and "windows terminated" messages - so it seeems even Windows doesn't like Windows (though it never suggested buying a Mac or loading Linux).
I'll try the ram reduction wednesday evening, new board may go in at same time. Watch this space though, tbh, I'm not confident in it all, lol.
Thanks for your time and concerns folks. Appreciate it.