I have 4 computers in my house and an AppleTV connected to my living room TV. I like to be able to use iTunes 9.0.2 to connect to the ATV to play music through it via the AirTunes function.

3 of my 4 computers are working for this function, but the last one is a WinXP machine and it cannot see the ATV or connect in iTunes for the iPhone remote service. I can ping the ATV from the command prompt and have verified that the bonjour service is running... I have reinstalled iTunes, disabled the firewall, and restarted the computer, the ATV, and the router with no luck...

Why can all my computers access this function except this one?