Alright... I've been trying to solve this myself for several days now.. but maybe some of you wonderful people can help me! I have an old iMac Rev A (or B?) and it is constantly freezing. It freezes in OS 8, 9, and 10.3.. but most frustrating is that it also freezes while trying to install an OS.. so right now it does not have an OS installed because of that. It will not boot up to my OS 9.1 disc.. but it will boot up to it's original 8.5 disc and a 10.3 disc.. However it always freezes near the beginning of the install process (often before it even writes to the HDD). I tried taking out the old RAM and leaving it with just the one (new) 256MB chip.. and that didn't work. It was freezing before with only the old RAM so.. I guess it's not the RAM. I have an identical iMac that doesn't choke on anything (never freezes) and it only has 96MB of RAM. I don't know what else I can do. I'm trying to use XPostFacto to put 10.4 on this thing (it's possible, I want to try it out at least) but it won't get through the first OS install and if it does, it won't get through the second (10.4). Even more frustrating is that I don't have any diagnostic software such as the Apple Hardware Test because the original iMac didn't come with any. If anyone can offer ANY suggestions at all, I highly appreciate it! Thank you!!