But I'm sitting here looking at my 24' Alu iMac and can see the faint impression of 3 or 4 Safari windows. The thing is, from the text I can make out, at least the top one is a very recent window which wouldn't have been open for long. Also, I have a screen saver and the display goes to sleep. For some reason the bottom left corner of the screen is most affected. Any ideas what's happened? I'll try to get a picture but I suspect it might not come out very clearly.