I just reinstalled my windows 7 ultimate and my transparency isn't working?

before i reinstalled windows 7 ultimate it worked perfectly fine but when i troubleshoot it says [ the current video card may support aero with a driver that is a compliant with the windows display driver model (WDDM). contact the manufacturer of your computer or video card for a WDDM- compatible driver ] if i put the aero theme on it is just the solid color and when i go to personalization everything is checked for best looking. i had a problem when i first installed this the first time but i figured it out somehow without access to internet so since we know it can be fixed, it would be very very appreciated if someone could help me out|||You have got the error message as you dint install or wrongly installed the graphics driver. Find out your graphic drivers cd which is compatible with win7 and install it else look it on their home website.