Need help!

Hi I am new to the forums and I need some help! I have a Dell XPS M170 laptop and I just formatted my computer with the windows cd it came with. Once I did that I installed the drivers from dell.com and now when i use it every image i see on websites look very bad as far as quality some of them are even hard to read. I have the upgraded video card too the Nnida 7800 Go Gtx. The computer was not like this only until i formatted it. Also it seems to be slower and i think its because of the video card as well but im not sure... Can anyone help!?