Hi everyone. My cousin has a early 2009 20" iMac, EMC No. 2266, Model No. A1224. He lives almost 1000 miles away from the nearest Apple Authorized Service Provider. Hence this post. He took his iMac to replace the HDD for a new one. The original one was failing. He took it to some computer-repair-guy that obviously never touched an iMac before. I'm saying that because, to open the iMac, he used some crowbar to open it from the back, resulting in all the case severly damaged. A total douche. Well, he finally accomplished to replace the HDD. But, since then, the iMac presents some sort of corrupted graphics issue. Let me illustrate the situation with some images and a video. http://d.pr/i/hnId (image) http://d.pr/i/HcrA (image) http://d.pr/i/OUi2 (image) http://d.pr/i/9ltG (image) http://d.pr/v/exaz (video) As you can see, there are some green vertical lines on the image. They are everywhere. They appears Lion, on Mountain Lion, even on the installers, even on the boot screen where you select from which drive to boot. Everywhere. So it is not a software related issue. It happens even on the Mavericks USB installer. It happens even on bootcamp Windows setup. If you look at the video closely, you will see that the green lines go alongside with the Terminal icon accordingly with the movement. I instructed him to use the Apple Service Diagnostics 3S132. The test fail SOMETIMES with the following output: 72 [Video 2D acceleration test failed] There is not other issues. No system crashes, no unexpected reboots, no performance issues. So, I am thinking on these possible causes: a) A graphics chipset related issue. A hardware failure caused by inappropriate manipulation of the computer. These are graphic glitches, or image corruption, caused by a malfunctioning chipset. b) A screen related issue. The screen fails to properly show certain colors. The screen is damaged by inappropriate manipulation. c) ??? So, well, what do you think is the most probable cause of this problem? I tell him to bring the computer to an Apple Authorized Reseller, but it is a long trip. He will do it, eventually. But, for now, he required my assistance. He wants to know if it is repairable and how much it could cost. Thank you everyone for your comments. PD: Sorry about any possible grammar errors or other typos. English is not my native language.