I have the same issue here, for some reason it keeps going back to Network Discovery - OFF, it will not stay on at all.
I have checked all the services that need to be on, they are on, I have event stopped the firewall, but that made no difference either?
I am in a Homegroup but just this computer refuses to keep network discovery on ?
Internet etc, etc is all fine, and my other 2 computers are fine, all talking to each other etc.
I am running build 7057.
Any ideas anyone?