Thanks guys for your responses.

FastGame, when I use Event Viewer, I get an Error from the Service Control Manager with the following message:

The hpdj service failed to start due to the following error:
The executable program that this service is configured to run in does not implement the service.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

I also get a Warning with this message:

The attempt to power off USER-TTBU8G1D9C failed

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.