I have a Mac G4 (MDD, dual, 1.25MHZ, OS X 10.5) which has problems lately. Don't now if it's logic board or what. A thread with problems is already posted (Help! My Mac G4 (MDD) won't start). I am looking to buy a used G5 that runs great. However, the person didn't supply details about the G5. Just that it has Adobe's CS4. On my G4 hard drive I have a whole lot of things I need. Would it be possible to remove the G5 hard drive and replace it with the G4 (80 GB) hard drive? Or can I upload everything from the G4 hard drive to the G5 hard drive? How can I do this if the G4 won't start? I have a new Mac-mini (10.7), with no software, nor internet connection. I seldom use it, turn it on about once per week. My G4 and all the stuff on it is super important. Sorry, I'm not a seasoned Mac mechanic. All I've done is replaced the optical drive and power supply, removed and replaced hard drive, removed fans, disconnected cables, thoroughly cleaned. Actually, when I open the Mac I cannot identify parts. For example, what and where is the video card? Which part is the actual CPU? Dual core means what? I know the PMU button and RAM slots. Thanks to anyone who can help.