This machine is pretty easy to get into. It is similar to the design of the 8xxx/9xxx series, but easier to get into. The first thing you need to do is open up a panel on the side of the machine. Press the button on the top of the machine and remove the side panel. Unlock the two green latches on the inside of the machine. Pull the top part of the machine up and swing it all the way around and set it down. Remove all of the PCI cards installed. Also, remove the personality card, which is the card with the sound ports and the optional modem and AV jacks. It is held in place by two screws. You are almost there! Remove the screws that hold the logic board in. Push down on the two latches that hold the logic board in, slide the logic board back, and pull it up and out.
Remove the side panel, as described above. The hard drive is located in the upper part of the computer. Remove the two screws that hold the hard drive in place, disconnect the cables from the back of the hard drive, and remove the hard drive.
Take out the side panel. That procedure is in the Logic Board section. The CD-ROM drive has a little front panel in front of it. The front panel is held in place by a tab. Pull the tab back, swing the front panel over and remove it. Remove the two screws and take off the metal panel in front of the CD-ROM drive. Disconnect the cables from the back of it and finally, pull the CD-ROM drive out.
Like the CD-ROM drive, the floppy drive has a plastic panel in front of it. Follow the CD-ROM instructions but do them for the floppy drive instead of the CD-ROM drive. For your information, the Zip drive is the same way.
Information provided by Doug Brown.