I am not new to Macs (it's almost been ten years!) but I am new to doing the upgrading myself. Except for adding some RAM, I have always stayed away from upgrading since it terrified me. (I was always worried that I'd break something.) Well, I picked up an old Quicksilver G4 (867 MHz) on eBay, and I'm going to be brave and upgrade the thing. I'm not afraid to upgrade the RAM, but it's the hard drives and to a lesser extent, PCI cards which are new territory. I have done some extensive Google searching, but would appreciate some comforting words and advice from other Mac people. Okay, so I went a little crazy and got several hard drives and PCI cards. I got a PCI USB 2.0 card from Otherworld Computing ( http://www.macsales.com ). I saw a video tutorial they had on adding a PCI card, and I think it doesn't look too difficult. Also, got the ATI Radeon 7000 64MB PCI Video Card. (I want to connect to a DVI monitor.) Should there be anything I should know about this? Is it just a matter of sticking it in the PCI slot and putting the screws in the right place? And lastly, I got an Ultra ATA 133/100 controller card (PCI) off of eBay, to add two more hard drives. (This is my biggest area of concern.) All the hard drives I am getting are ATA-100. (I was led to believe this is what the G4 supported.) My first plan was to add a cheapo little 40 GB HD on top of the factory shipped hard drive. (I have seen tutorials on YouTube on how to do this. Stick it in, screw it to the brackets, and put in the power and data cables, right?) Then using the Ultra ATA controller card, I have two larger drives (250 GB and 320 GB) which I want to put in each of the other two free bays. I've also purchased 40-pin connectors (those ribbon-looking things) to connect them to the controller. And I am led to believe that there are some additional free power cables inside the Mac that I can connect to each of these two additional drives. Will this all work? Am I missing something? And my biggest concernwill this make everything toasty hot inside? If heat is an issue, what can I do to avoid it? Just have one drive connected to the ATA controller card? Not have a drive piggyback on top of the factory drive? This will be my secondary Mac (I use an Intel Mac primarily) so this isn't life and death, but needless to say I don't want to mess up this old G4 if I can help it, and I do plan on using it at least a little. Thanks for any help you can give me!