Black screen until windows starts

I built a computer for my father. The first boot and during bios setup everything ran fine. A day later the screen stays black until window loads which makes me miss the bios/start screen. When I am in windows it will not let me change my resolution from 1200x720. Although when I play a game the screen turns black for about a minute then the game will start with the higher maxed out resolution. For some reason I feel that the computer is only using the graphics card during games and the built in graphics card during normal windows opera tion. Does anyone have any idea what is going on?
AMD 64x2 6000
8 gig g skill ram
evga 9800 gtx gpu
500 gig HD
24" acer p244w
windows vista 64 bit

Well it can't be using the integrated graphics if you have it plugged into the video card. What motherboard is it?