Mine does that as well. Except it flashes for a while, and then the graphics screw up and everything goes mysteriously black. Work of the devil!
I had to download a patch just to get it running, so the answer is: Go Back To XP
Vista is known to have problems with games. Even with current, not just older. A friend of mine has the same issues with Lord of the Rings Online (runs perfectly well on a way worse system with Windows XP). The main issue is that Vista uses up ur ram. If u have less than 1.5 gb ur fucked. Try to get a ram cleaning program to make it work slightly better but i'd suggest u to get back to XP.