Question : Problem: ITunes stopped detecting AppleTV

Everything worked with AppleTV and iTunes for months, but suddenly the PC running iTunes never detects the AppleTV anymore.  I've tried everything in the Apple troubleshooting article (disabling firewalls, reinstalling iTunes, restarting the AppleTV, rebooting everything).  The AppleTV cannot see the iTunes PC either.  But, the AppleTV sees other PCs running iTunes, and the other PCs see the AppleTV.  It's just the one PC that stopped detecting the AppleTV.    I could switch the AppleTV to synch with iTunes on a different PC, but that's not what I want to do.  I want the AppleTV to continue to sync (as it did since I got it) with the particular PC.  I have no recollection of changing anything recently on the problematic PC.  I even confirmed that one of the other PCs can detect iTunes on the problem PC when I share the library from the problem PC.  But for some reason, the AppleTV and this PC refuse to see each other.  

Answer : Problem: ITunes stopped detecting AppleTV

I gues that I figured this out myself (after receiving no answer for 2 days).  Somehow the troublesome PC must have thought that it was only authorized for "streaming" connection to the AppleTV (although the AppleTV didn't show up as a valid AppleTV for that iTunes connection>  I had to tell the AppleTV to stop synching to that copy of iTunes, and then add the PC back as a "new" PC connecting to iTunes.