Has artifacts attached to the desktop icons and mouse pointer.
I've seen this before but don't remember the problem. I ran an older version of tech Tool Pro and the artifact ( square and looks like multiple lines of the same bar code). The artifact was present on the mouse pointer icon with Tech Tools ruling out a software problem. The rest of the screen looks just fine. To me this indicates a video card failure but I think it's built into the logic board on this machine.
Is this a good question?