Just upgraded to windows 7 from windows vista and now my monitor flickers when i get on the internet! please help!

I have a Dell studio XPS 64 bit. I dont know much about computers at all, so im in a bit of a panic. My laptop only does this online, Its not my whole motior that flickers its only things like little advertisments or when i get on games online. sometimes just the whole page will flicker and Its driving me crazy. sometimes my computer will be fine and not do anything but other times it freaks out like that. It never use to do this with windows vista, it all started when i upgraded to windows 7. other than that there is no problem.  Please help me :(