I have come across this problem myself.
1), The people who designed this game were kinda lazy, it doesn't work on anything other then a godlike xp pc that has the exact specs given as recommended(no better, no worse)
2), Install patch:1a
3), Install patch:1b
3), Install Vista service package(and make sure you don't pay, if you do it's a scam)
4), Search: SWKOTOR2 vista patch: on google(dunno where you live so don't know whether to give american/european link etc...)
This will still leave many problems but it will make a hell of a differance(avoid dantoine and korribian till you find a better solution)