Is it possible that the image didn't move for some time, and became somehow burned on the screen? I am not remotely technical but this happened to me one time, I'd left the eBay screen up with no screensavers and I could see a sort of shadow of it on the screen after I'd closed down. The techies will know what it is, I am sure, but I as told that it was a bad thing, and that we should make sure that there are some moving items on the screen all the time if you leave it for a while.