Hi As you can see in the picture Im having a pixelproblem of some sorts. I get these dots regulary. They blink rapidly and disappears somtimes when i change desktop or open a program. The end result though is always the same: The whole screen freezes and lastly the mouse stops working and I have to shut down manually. Ive had the Imac examined by a company. They came to the colclusion that I had a defect RAM. I got rid of the old RAM and bougt a hole new set. It hasnot helped as you can see. I have also tried to clean install Mac OS. It took a long time before the dots appeared, and for a couple of days, I though I was saved. But they came back. Has anyone experienced somthing similar? - or know what is causing these dots and what to do about it? I am at a los. I have, of couse tried to search the problem, but to no avail.