Deleting the game

Im thinking of deleting GBTVG from my Xbox and then starting from scratch but i have some questions:

At the moment i have 48/50 achievements only 2 missing are Payday & No Job To Big (On mine under NJTB it says defeat all most wanted ghosts which i think its wrong), if i restarted the game would i be able to get the last 2 achievements (i was on 47 before the patch arrived)

cheers

Probably not.

I think you need a new Xbox Live account to reset that and get it.