after lots of trial and error, i finally managed to get Bioshock running in 7000 32bit. i had to run the installer in Vista compatibility, otherwise it got confused by DX11. then i actually had to install DX9 from the DVD (!) otherwise i just got a blank screen. finally, i had to run the game in XP compatibility mode, otherwise i got no sound during the game.
so now it works, but i often get artifacts on the screen during play which i never saw on XP