Hello Boston 1961,
It sounds like you are not able to access iTunes from your Apple TV using Home Sharing. I found an article with steps that I think would help with this issue.
I recommend reviewing the full article below:
Thank you for using Apple Support Communities.
Had the same problem. I also have Windows 7. I connect through a Motorola modem and Airport Extreme router. Went through my Airport Extreme and changed IPv6 to IPv4 and everything worked.
I'm still having issues showing all 102 movies in my Apple TV Library, but I can Airplay them from my computer.
So after a Windows update and a reboot, I cannot access my library on my Apple TV.
I have an iPad and iPhone as well.
My Apple TV does not detect my library, my iPhone does not detect my library, my iPad did detect at first but now doesn't. I have:
Reset my network router
rebooted my computer
reset my network adapter
turned off wifi on my computer and used wired connection
Turned off and on hoe sharing on itunes, Apple TV, iPad, and iPhone
And still nothing.