Push up on the two tabs under the front panel (a screwdriver helps) and pull the case top toward you and then take it off. Flip the two plastic panels off to the side (one's on the right, one's on the left, the one on the right is small). Two latches hold the internal chassis in. Unlatch them and flip it over to the right. Remove the PCI cards. Remove the personality card by removing the two screws that connect it to the back, then taking it out. Disconnect the cables connected to the logic board, then remove the screw inside the round cylinder. If you want to remove the processor board, unscrew the screw that screws the wire connected to the processor board to the logic board, then press the latches by the front of the motherboard, then slide the logic board out.
Follow the steps above, and after you flip the internal chassis to the right, disconnect the cables from the hard drive, and pull the tab by the front of the hard drive while pushing the back of the hard drive, then take it out.
Remove the case top, and then disconnect all of the cables from the CD-ROM drive. Pull up on the tab on the front of the CD-ROM drive and pull it out of the machine.
Remove the case top, and remove the shield that goes over the Zip drive slot. Next, remove the shield in front of the floppy drive. Flip the plastic panel on the right off to the side (it's small, just behind the floppy drive). Disconnect the floppy cable. Pull the rails that hold the floppy drive in outwards and push the back of the drive.
Information provided by Doug Brown.