[crazycylon]

A vertical white line about 1" (2.5 cm) high now appears about 1/4" away from the mouse pointer. I have been trying to get rid of this white line. I have zapped pram, rebuilt my desktop, ran Tech Tools Pro to check video and file structure etc. I still can not get that line to disappear. This line follows where ever I move the mouse pointer.

Other than the white line, system appears to be functioning well. Any advice on how to get rid of this line would be appreciated.

how about reinstalling your video drivers? or trashing some preferences, like system, macos, etc.

[crazycylon]

Did that , didn't work. Ran some more tests. Problem now detected in VRAM. Failed tests 10101010, 11110000, 00001111, 11111111, 00000000. Repeated test after going back to base extension set. Failed tests again.

Looks like I will be making use of my Applecare Extended Warranty.