On PC 1, I set up sleep after 1 hour of idling. It's connected to the router with a cable.
Then there's a PC 2, connected with wi-fi. If PC 2 is on, PC 1 won't go to sleep.
(There's also a PC 3, connected with a cable, and it doesn't prevent sleep.)
Why is that?
Does wi-fi have anything to do with it?
All PCs are running Windows 7 and have almost identical configurations, at least PC 2 and PC 3.