I have a problem similar to
this one. Windows Firewall prevents File and Printer sharing from working
and Why does File and Printer Sharing keep turning off in Windows 7?

I cannot turn on Network Discovery.

This is Windows 7 Home Premium, x64. It's a Dell XPS 1340 and Windows came installed from the OEM. This used to work. Now it doesn't. I don't know what has changed.

In windows Explorer, the UI looks like this:

When I click the yellow panel that says "Click to change...", the panel disappears, then immediately reappears, with exactly the same text.

If I go through the control panel "Network and Sharing Center" thing, the UI looks like this:

If I tick the box to "turn on network discovery", the "Save Changes" button becomes enabled. If I then click that button, the dialog box just closes, with no message or confirmation. Re-opening the same dialog box shows that Network Discovery has not been turned on.

If I turn off Windows Firewall, I can then turn on Network Discovery via either method.

The machine is connected to a wireless home network, via a router. The network is marked as "Home Network" in the Network and Sharing Center, which I think corresponds to the "Private" profile in Windows Firewall Advanced Settings app. (Confirm?)

The PC is not part of a domain, and has never been part of a domain.

The machine is not bridging any networks. There is a regular 100baseT connector but I have the network adapter for that disabled in Windows.

Something else that seems odd. Within Windows Firewall Advanced Settings, there are no predefined rules available. If I click the "New Rule...." Action on the action pane, the "Predefined" option is greyed out. like this:

In order to attempt to allow the network discovery protocols through on the private network, I hand-coded a bunch of rules, intending to allow the necessary UPnP and WDP protocols supporting network discovery. I copied them from a working Windows 7 Ultimate PC, running on the same network. This did not work. Even with the hand-coded rules, I still cannot turn on Network Discovery.

I looked on the interwebs, and the only solution that appears to work is a re-install of Windows. Seriously?

If I try

netsh advfirewall firewall set rule group="Network Discovery" new enable=Yes

...it says "No rules match the specified criteria"

EDIT: by the way, these services are running.

DNS Client
Function Discovery Resource Publication
SSDP Discovery
UPnP Device Host

in any case, since it works with no firewall, I would assume all necessary services are present and running. The issue is a firewall thing, but I don't know how to diagnose further, or fix it.

Q1: Is there a way to definitively insure the correct holes are punched through the Windows Firewall to allow Network Discovery to function?

Q2: Should I expect the "predefined" firewall rules to be greyed out?

Q3: Why did this change?