What about your display driver? Check device manager to see if it shows the device by name and that it's working correctly. If you encounter a yellow question mark instead, this means the proper driver could not be found and Windows is using some failsafe driver.
I had Windows XP home. I have installed ( new installation, not upgrade) Windows XP SP2. After that everything looks ok except display. if i open any new window say notepd or wordpad or any other window and try to move any of the active windows by holding it via my curser then active window moves but it is looks like waves. It looks like active window which one i am trying to move cretes some wave effect within that window. Active window does not move smothly. What might be wrong?