My late 2009 27inch iMac froze with funny pink ‘squares’ (see first photo) popping up all over the screen . I hit the power button, for a restart and all was fine for an hour or so when the same thing happened. This time I unplugged the iMac from the power and waited 10 mins or so. Upon start up the startup screen had 5 or so pink vertical lines running from top to bottom (see photo 2) and the system promptly froze with a plain white screen.
I have reset the SMC and PRAM but still get the pink lines upon start up. After a few power offs and restarts usually things start working again. I wondered if anyone had any idea as to what this problem might be?
7 years use out of a computer used most days, albeit not all that intensively, is not bad, but I’d hate to throw this out if it is only a small problem. Thanks in advance for any advice/comments