Be able to earn Achievements after getting reset!
This tutorial will teach you how to be able to earn your achievements back after you got them reset and get you removed from the "cheater" zone.
Add the Xbox 360 Dashboard to your list (FFFE07D1)
Delete the Xbox 360 Dashboard from your Game History.
(You may have to wait a while until you are able to delete it from your game history. This may even take up to 2 days)
Your Bio, Gamerscore, and Game History will now be gone.
Wait a little while for it to update on Xbox.com.
Once you see that you have no Gamerscore or Game History on Xbox.com just recover your gamertag
Credit goes to EasterBunny