I had trouble with one of my SBs connecting to SlimServer after the latest round of Windows updates, earlier this week.
I always run "Tune-up Utilities"
http://www.tune-up.com/ after each update.
Another very good program is CCleaner
http://www.ccleaner.com/Each of those programs usually find some "problems" or conflicts in the registry after updates.
After running the "Tune-up", I reset my router and checked the IP assigned to my music server (I use dynamic IP).
Sure enough it had changed and the SB couldn't find it. I hard re-booted the SB (unplugged the power from it), did the factory reset (hit the "add" button when the SB first displays SqueezeBox on it's screen) and then went through the whole set-up including the assigning of IPs.
All is well, now.
I routinely check out 6-8 SBs a week through my system and I have had little to no problems having them connect and stay connected for extended periods of time. I did spend a lot of time trying different routers before settling on the NetGear WPN824.
I also replaced my wireless telephones with 5.8 Mhz models. I am far enough away from my neighbors that their phones don't bother my wi-fi. There are up to 6 different networks able to be picked up from various areas of my house. Luckily, the SB doesn't seem to mind them.
You can use a static IP for your music server and this "
should" prevent troubles when the computer restarts after updates, etc.