Controller lost connection to my local Logitech Media Server - how to get it back

Has been working flawlessly for a year, then yesterday (a Monday) it could no longer connect to the local LMS. LMS running on a Windows7 PC, SP1, and the PC is on the network. Connection is wireless. Controller, PC and Squeezebox all show up on the network and are connected to it.

Diagnostics show:

Running 7.7.3.r16662 and the MAC address is displayed
Network Health: All network tests passed successfully
Wireless network wireless signal: 100%
Server info: this shows the mysqueezebox.com address, Ping OK, TCP ports are OK, I'm informed I'm registered; Logitech Media Server: Not connected, Library name not connected, Ping: Not connected
Networking: connected to the right network

I guess this could be due to Microsoft Security Essentials. I checked and LMS is allowed through the firewall, and all incoming Logitech communication is allowed, and the TCP is activated, and LMS is prioritized.

Under Software update it said "begin update (7.7.3 r16662)" and referred to the archive. Since it's already running this very software version, I didn't get why it was suggesting an update. Nevertheless, I accepted the update. No change.

So, any suggestions of how to get the connection to the local version of LMS?