A flaw in the Xbox Live system
has been found where if you use an email address to register your Xbox Live account that can expire after a period of inactivity and does, you are forced to create a brand new Gamertag and thus lose all your achievements. Hotmail is one such example and I for one use that for my registration and don't use it as my email account. I don't even check it anymore so I guess I better fire some emails from there to prevent ths from happening. Right now there is no way of recovering your achievements or account even if you setup additional email accounts. I don't even know if you can change the primary email address for the Xbox Live account, but I assume there is. I haven't checked but I will be doing that this evening.