I've been having some trouble with my iMac G5, and the hardware test CD indicated it was a video card problem. This was expected, because the video was all jittery and the system became terribly unstable. So, I called up Apple to get them to send me a new midplane assembly, and the (very nice) support person was having trouble understanding why it wasn't on the list that she could ship out. She did some investigation, and discovered that it was intentionally not on the list anymore because it's a no longer considered a user-servicable part. So now I have to take it into an Apple repair shop - which really sucks, because I live quite a distance away from one, and I just had surgery and can't drive. Just FYI, in case others had to go through the same thing.