I am having a problem with my computer. I am running windows vista. whenever I turn on my computer I get a white desktop with a windows warning message. It is telling me I am infected with two viruses, but I do not think it is a windows message. I cannot change my background back to what it was, all my icons are still there and programs run fine but I know something is wrong. This problem just happened two nights ago. I have run mcafee and it found nothing. Please help