My iMac desktop computer won’t boot up. It shuts down immediately after the start up chime.

1. Shut down the computer.
2. Unplug everything from the back of the computer including the computer's power cord.
3. Press and hold the power button for 5 seconds.
4. Release the power button.
5. Attach the computer's power cable (don't plug in anything else).
6. Press and release the power button to turn on the computer.

If it boots to a login screen, then plug everything else in (keyboard, Ethernet cable, etc) and log on. If it still doesn't get to a login screen, please fill out a Web Help Desk work order ticket (on someone else's computer).