Dell Dimension 4400 - Manual (Page 22)

Note the routing of the DC power cables underneath the tabs in the computer frame as you remove them from the system board and drives. It is
important to route these cables properly when you replace them to prevent them from being pinched or crimped.
6. Remove the two screws that secure the power supply to the back of the computer.
7. Press the "PUSH" button located on the floor of the computer frame.
8. Slide the power supply toward the front of the system approximately 1 inch.
9. Lift the power supply up and out of the computer.
Replacing the Power Supply
1. Slide the power supply into place.
2. Replace the two screws that secure the power supply to the back of the computer frame.
3. Reconnect the DC power cables.
4. Close the computer cover .
5. Connect your computer and devices to their electrical outlets, and turn them on.
Replacing the System Board
Removing the System Board
1. Shut down the computer .
2. Turn off any attached devices and disconnect them from their electrical outlets.
3. Disconnect the power cable from your computer, and then press the power button to ground the system board.
4. Open the computer cover .
NOTICE: To connect a network cable, first plug the cable into the network wall jack and then plug it into the computer.
CAUTION: Before you begin any of the procedures in this section, see " Safety Instructions ."
NOTICE: To disconnect a network cable, first unplug the cable from your computer and then unplug it from the network wall jack.