Home Forums Networks & Cross-Platform Networking When modem is on, computer won't sleep

In the Energy saver, when you uncheck "wake up for network administrator...", does this stick? If you restart, does it revert back to checked? If yes, click on the padlock. Is the test admin account (see Donikatz's post above) doing the same?
I am also wondering about the modem configuration. You might like to access the modem through Internet and see what settings does it have. I would also call Comcast and try to troubleshoot with their tech. They may have heard of this issue.