Background: I'm on a PC with Windows XP. Got ATV 2-3yrs ago and use it on a WIRED network. Had the "need to open ports" issue and fixed it. All is good. VERY fast synch speeds and no problems. Love the ATV.....until...intalled latest iTunes update (9.??) 2 weeks ago. ATV no longer in device list. Hours of searching and rebooting and resetting and I finally find the answer is the latest Bonjour has a bug which causes this issue. Uninstalled and reverted to the previous Bonjour. ATV is back but in devices. Because all my content was wiped, have to resync. I only sync a small amount of data to the ATV...1900 songs. Usually takes less than 20 minutes. 36 hours later the end is nowhere in sight so I stop the sync. I made no changes to my network setup. I tested youtube and internet radio connectivity and they are fine. Quite fast actually. I reboot the ATV. No better. I reboot the computer with no improvement. I update the ATV to the latest version, still no luck. (Incidentally, I avoided the new ATV software due to a known issue with FLAC and WAIFF music files. Not sure if this has a fix yet). Factory settings restored and still no luck.
Basically, what could possibly have changed to make a wired ATV unusable when it has been fine for so long? This one really has me stumped.