Dell OptiPlex 360 (Late 2008) - Manual (Page 84)

84 I/O Panel
3 Replace and tighten the screw that secures the I/O panel.
4 Reconnect the cables to the system board.
5 Follow the procedure in "After Working on Your Computer" on page 17.
CAUTION: To connect a network cable, first plug the cable into the network
device and then plug it into the computer.
6 Verify that the computer works correctly by running the Dell™ Diagnostics
(see "Dell Diagnostics" on page 136).