Okay i try playin the sims 2.
I have windows vista, when i have a family open/house all the walls are red black and flashing and other graphics are rubbish and dodgey too.
BUT i know two more people who play sims 2 on vista and theirs are fine.
I tryed updating my graphics card but its up to date?
Whats the problem?

get rid of Windows Vista for a start...i have it and its rubbish - getting a Mac instead

i dont think vista likes sims 2

I don't play games anymore but I always see my brother struggling with playing games on vista too,but I know they are different versions of windows visa so you can't be sure if that is the problem.
try to update the game and your windows,I'm sure they have to have something in their website to help you.
good luck

i have windows vista too. when i play, my sims get like all strached out and a bunch of colors end up on the screen. itss soooooo hard o explain but i can still play, its just annoying... i think u need a better grphics card, but i keep forgetting to tell my mom to get a new one for me on my laptop... u can go on the website or just google search the kind of cad u need, its easy but i aways forget =) hope this helps
~caroine

You need to upgrade your graphic card. Usually downloading new drivers for your card won't be enough.

To learn more about flashing red and black walls read here:
http://www.sims2wiki.info/wiki.php?title=Game_Help:Red_Flashing_Walls