Ok, well I went through all those steps, totally uninstalled the drivers and got new ones. Still crashed within a couple mins of opening a game.
Also ran memtest, no errors for 19 passes...
I'm not sure if this Windows 7 is official or not, I bought this computer second hand, but it's less than a year old and was very well maintained.
What else could be causing it? And why are the dumps unreadable?