After Working Inside Your Computer - Dell Precision Tower 3420 Owner's Manual

1. Click Start.
2. Click the arrow in the lower-right corner of the Start menu and then click Log off.
2. Ensure that the computer and all attached devices are turned off. If your computer and attached
devices did not automatically turn off when you shut down your operating system, press and hold
the power button for about 6 seconds to turn them off.

After working inside your computer

After you complete any replacement procedure, ensure that you connect any external devices, cards, and
cables before turning on your computer.
1. Replace the cover.
CAUTION: To connect a network cable, first plug the cable into the network device and then
plug it into the computer.
2. Connect any telephone or network cables to your computer.
3. Connect your computer and all attached devices to their electrical outlets.
4. Turn on your computer.
5. If required, verify that the computer works correctly by running Dell Diagnostics.
7