Apple TV and Home Sharing

I recently purchased the latest Apple TV for the sole purpose of being able to share my music, TV shows, and Movies and watch them on my television. I set everything up according to the instructions provided, even hard wired the system into my network. I have iTunes running on my machine and have enabled Home Sharing on both my pc and on Apple TV, I am running Windows XP Professional on my computer and my network runs through a Linksys 10/100 5-port workgroup switch. I have ensured that the following ports have been enabled on my computer firewall and on the worgroup switch firewall.

Six network ports are used by Apple TV for communications on your network.

* TCP port 123 is used to communicate with a network time server.
* TCP port 3689 is used to communicate with iTunes while using the iTunes Library Sharing feature.
* UDP port 5353 is used by Apple TV for automatically finding computers with iTunes on your network using Bonjour.
* TCP port 80 is used for communicating with podcast servers.
* TCP port 80 and 443 are used for basic and secure communications with the iTunes Store via the Internet.
* TCP port 53 is used for regular DNS.

I have uninstalled and reinstalled iTunes on my pc, repeated disabled and enabled Home Sharing on both the pc and on Apple TV, checked for the most recent software updates, signed in and out of the iTunes store on both, rebooted the computer, reset my network connections, etc.

In addition, I was on the phone with Apple's Express Lane service technician, who simply told me to try the things I had already tried...

After all that I still am unable to get Home Sharing to work (which as I said was the whole purpose for purchasing this thing in the first place). I am just about read to throw the stupid thing out the window and never buy another Apple product.

Can anyone help me figure this out.