Factory restore: According to Apple, "Press and hold both Menu and Menu down/scroll (-) on the Apple Remote for 6 seconds or until the status light blinks amber." Then select your language, and factory restore.
Networking: The Apple TV uses UDP port 5353 (Bonjour) and TCP ports 3689 (iTunes Library Sharing), 80 (iTunes store), and 443 (iTunes store).
LEDs: The status LED can be white or amber. Apple has a table listing all permutations.