Is there a way to reset stats/level/prestige?

[haxrevolution]

My brother fucked up my MW3 using lolbie's stat changer (nice cheat btw)Now i've got like 300 hours of gaming with 2x xp and 2 xp weapon level, 10 custom classes and all prestige shit unlocked.If this cheat is able to modify game settings,there must be a way to reset it,like MW2. But how?
Also when i try to play it doesn't start and a steam window pops up saying the game is not ready to play.Why?I see my friends playing on MP.

[haxrevolution]

please close,i'll just go to level 80 prestige 10 and reset everything with prestige tokens.