I'm running the game on Vista, and through Gametap, and when I try to play the first and third races, the game crashes halfway through. Needless to say I can't finish the game if it crashes in the third race, so I'm a bit upset.

Any ideas about what to do? I've tried running Gametap in Windows XP SP2 mode, to no avail.

Is it just a crash to desktop or do you get an error message? In any case post your dxdiag here, perhaps there's more information to be found there that explains the problem.