HT1750: Intel-based iMac (Mid 2007) and later: How to find the serial numberLearn about Intel-based iMac (Mid 2007) and later: How to find the serial number
565 Views 2 Replies Latest reply: Nov 20, 2012 2:01 PM by robinfrombirchington
Currently Being ModeratedNov 20, 2012 3:27 AM (in response to robinfrombirchington)
It sounds like either your video display or graphics card is failing. If you insert your Original Installation Disk that came with your iMac, you can run the Extended Apple Hardware Test to try to narrow th hardware issue down.
Hope this helps