Contribution d'origine par : Alec ,
I do not like to take chances with power supplies. I think it would be in your best interest to purchase one just in case. It definitely sounds like a power surge hit your computer, and I would hate for it to be damaged by a bad power supply. As for the green pixels, it sounds like those are GPU artifacts. It’s likely that the power surge shocked your GPU. I would replace that as well. You’re fine to use it right now, but you’ll probably notice lots of other issues as you do, so replacing that should be a priority. [https://www.ebay.com/itm/Apple-iMac-21-5-A1311-Late-2009-ATI-Radeon-HD-4670-256MB-Video-Card-661-5308/132510790916?epid=1700366830&hash=item1eda423504:g:JLEAAOSw6LBa4JzE:rk:3:pf:1&frcectupt=true|This looks like the correct part], but double check to make sure. [guide|1852|This guide should get you to where you need to be in the iMac]. Good luck!