THIS IS THE ANSWER The nvidia graphics card has a recall on it for Mac Pro model # MA610LL, late 2006 models. Sold as 2007 models from early 2007 to end of 2007. I have been fighting apple for years to have this recall fixed under extended out of warranty repair. Also, when it was covered. Apple, would not replace the defective graphics card. They, APPLE, finally agreeded to do a covered white glove inspection and repair. As should have been done, while it was under warranty. Instead, they replaced a failing optic drive, with a third party optic drive. They did not even address the graphics problem. I got it back, shipped via fed ex. In a wet, BUSTED open apple repair box, from the abuse in transit and drop on front covered brick porch. Fed ex label torn away address part left. No Apple security tape present. Signature required according to apple. Fed ex just left it. No invoice detailing repair, what they did. And computer password changed. Apple could not give me the password, that they swear they did not change. So, I had to do a system restore. That worked. Then, the optic drive just replaced by apple failed day two while updating to snow leopard. It would not read the install CD. SO, APPLE SAID DO ANOTHER SYSTEM RESTORE. THE OPTIC DRIVE WOULD NOT READ SYSTEM RESTORE DISK 1 nor would it eject. So, I sent it back to them overnight . Apple, sent an email stating repair complete. They had my Mac pro model MA610LL , less than 48 hours. Nothing repaired. Systems disk still stuck in optic drive. I called them and was berated, belittled, & accused by a Senoir tech. He was accusing me of replacing the optic drive with a third party drive, that it had a third party hard drive in it and micro fractures In the logic board. And nothing wrong with graphics Card. I told them bull .... They gave me an estimate of 1,297.46 . I asked for a copy of that took 3 hours plus on phone passing me off. Finally, they sent it. So I could file a claim against Fed Ex. Apple and fed ex have a deal. If apple will not push claim the customer can not. Or even speak to fed ex. All the problems with this model MA610LL AND RELATED MODELS. Are all the same, overheating problems, unexplained red black graphics, and failed optic drives. They, Apple is aware of and they will not stand behind the know defects. Apple passes you off from tech to supervisor over and over and then slides it under the rug. Stating they have no record of your repairs, no notes nothing. If I had money I would legally per sue them. But I do not. So after going on 3 yrs of being passed off. I call it the great apple pass off. I am going to try to repair my Mac myself. I do not even know how to or where to start. I am glad I found this web site. I need instruction on how to open case to get to optic drive, hard drive, logic board and graphics card. I Have no clue what all this looks like. But it is being filmed for YouTube etc. And for my own purpose for putting it back together. Wish me luck any advice greatly appreciated. Also, I want to see all the third party components apple claims are inside my Mac.