Seasons Graphics Issue

[almstfms6688]

Hi,
So I don't know what's wrong... I have Nightlife and Pets, and I recently got Sims 2 Seasons and installed it. The night I got it, I played it for an hour and it was perfectly fine. The next day I moved to a different house up at school and when I went to play the game, after I started it up and went into the Veronaville neighborhood, the graphics were all grainy! It would be fine if I moved the mouse around to move the picture around, but when it was still, the grainy graphics would appear. The same thing happens when I go into a house as well.

I've updated my video card, installed the patch for the game, and I know all my requirements on my computer fit with the requirements needed for the game. Is there anything that can be done so that I don't have to uninstall it all and lose everything i've gotten? This is so aggravating!

Thanks for your help.