there is only one pcie... so that doesnt fly
what I did now is start in safe-mode with the x800, select the 8800 driver, shut down and swap cards.
when booting with the 8800 then, it shows the animated win7 logo... and then just restarts without errormessage.
when I disable the automated restart in the bootmenu, it comes up with a BSOD right after the logo, saying there was hardware damage. The card worked just fine under xp, so I think we can rule that out.
THere is one more thing, I'm not sure if it matters at all. The display I'm using is VGA, the 8800 is DVI out. So I'm using this converter inbetween. Does that make a big difference? Would be weird.
Thanks for your input