Demo problems.

I've been having problems running demos for games the last week. I've tried Fifa 2006, COD 2 and AOE 3. Fifa 2006 has this weird problem where the teams keep switching when I'm not touching the keyboard. In COD 2 there's an error that my 9800 doesnt support Alpha blending and AOE 3 wont install because there's an error 1935, then 1603(fatal error). I'm so confused, and any help would be appreciated. If its the card(ati radeon 9800 pro aiw) then I can take it back to futureshop for a new one.