Dell Dimension XPS 50 Reference Manual page 32

chassis cooling fan
system board
filler brackets
chassis
card-guide assembly
(contains primary hard-disk drive)
2-6 Dell Dimension XPS Txxx and Txxxr Systems Reference and Troubleshooting Guide
power supply
bezel
reset button
DC power cables
diskette-drive interface cable
secondary hard-disk
drive bracket
drive cage
power indicator
power button
hard-disk drive
access indicator
drive
bays
(typical)