The Power Mac G3 All-In-One expands on the pull out motherboard idea the Color Classic introduced. With this model, however, the drives come out along with the motherboard. To remove the logic board, first remove the four screws on the back of the computer. Pull the slide-out back part out partway, then disconnect the four cables that are still connected to the rest of the computer. Press the tabs toward the bottom of the machine, and pull the "motherboard carrier" out the rest of the way.
Remove the "motherboard carrier" out of the machine and then disconnect the cables from the hard drive. Pull the tab up and pull the hard drive out of the carrier.
Disconnect the cables from the back of the drive. Pull down on the bottom of the carrier and pull the CD-ROM drive's tab up at the same time, and pull the CD-ROM drive out.
Pull the tab up and pull the floppy drive out half way. Disconnect the floppy cable, and pull the floppy drive all the way out. The Zip drive comes out the same way, except you remove the cables from the Zip drive instead of the floppy drive.
Information provided by Doug Brown.