hey i found a solution to fix corrupted account on gears of war 2 and it is legit cuz my was corrupted just follow the steps below:
1. Launch Gears of War 2 without signing in.
2. Go to Training Ground and pick the Submission training.
3. The game will ask if you want to play without a profile, hit yes.
4. While loading into the Submission training, quickly log in with your account.
5. No more freeze up, your profile has been reset and the game goes back to title screen
only set-back is that your in-game achievements will be reset but the ones u earned on ur xbox live profile will stay the same
comment if it works or if u have any questions