I'm with Kerry, sounds like a problem with the video card, either a driver problem or a new problem with the card itself. I've upgraded a couple of my computers to Win7 and while it generally goes smoothly, it's not uncommon for there to be a random problem with a driver for one component or another. Do you have some way of determining the original configuration of your computer? Many manufacturers offer a means on their web site to enter a service tag or other unique number from your computer, which then generates a list of all the components installed in your computer. From there you can research compatible drivers. If that doesn't make sense, PM me and I'll try to walk you through it.