LMS doesn't find players, players can't connect to library

Hi All;

I have enjoyed my squeezeboxes for years and year, mostly trouble free. An occasional hard reset here and there. I have 4 receivers (2 on ethernet, 2 on wifi) and 2 controllers, and LMS on a win 7 machine. Yesterday, there was an issue with my Semantic antivirus that I had to fix by upgrading from version 11 to 12. In order to do that there was a "base engine xxx" service that had to be added inorder for semantic 12 to be able to install.

That was the end of my system. I have tried everything, hard reset of controllers and receivers, disable the antivirus and firewall, reboot the router, clear cache, even uninstall and reinstall LMS. No go. Here is what (doesn't) happen:

The system can play from mysqueezebox.com
The web control for LMS doesn't see any players (receivers), or sometimes the pull downs show the names of them, but you can't select them
When the players try to connect to the library, it fails. It does know the name of the library, as it say it in "connecting to..."

So, I have another machine that I have been prepping for a family member. I installed LMS, built a library of a few songs, scanned them in, rebooted the controller and a player, and viola! It works fine on the other machine.

So, the good news is that I know it's not the players or the routers. the bad news it I don't know what it is. Since I am a firm believer in "the last thing you changed messed it up", I think it was my wrangling with windows and semantic. Does anyone know what has to be configures in what way with regard to windows allowing LMS to work properly? Any help would be welcome, as I dread the data backup and reinstall of windows 7

Thanks, Jim