Game's Flashing.

The Sims 2 used to work perfectly on my computer. Although a few weeks ago, my computer crashed and I got a blue error screen reading "Ati2dvag is in an infinite loop". I have a Dell Dimension E510, and a ATI Radeon video card.

I got on the phone with Dell Customer Service, and they sent me a new video card, saying the old one was defective. Well...after installing the new card, I'm still having problems!

When I play the game, my graphics are good but it's all flashy and weird. How can I get the colors and flashing to go away?

Make sure you are running the latest ATI drivers and DirectX and try reinstalling them, also playing around with different drivers ie older ones can make it more stable, try installing the drivers that came with the video card.

How do I get new drivers? How do I know which ones to download?

Find www.ati.com and under drivers & software you should be able to find the correct drivers for your card, there are plenty of installation aides and guides on the site as well.
For DirectX go here.

If you go to the dell website they have a driver download area, it will ask for your service tag which you can find on a label on the case somewhere, enter the tag and it will identify your system and let you download the drivers based on the hardware that you have in your PC when it was shipped to you.