Mw3 Version 1 rank hack?

Hi I have the original non updated version of mw3 released by reloaded. I only play survival mode solo, but somehow my damn stats reset and im back to 2% complete on co-op so i dont have any guns unlocked. Iv seen plenty of trainers and rank unlockers but none that seem to work with a non legit/non updated version of the game. Could anyone help me out with this? Many thanks guys

See if they have any patch for the game update it to a later version that could solve it ..

Just try using the CE tutorials found in the forums.
Basically just search your current XP in Cheat Engine and once you find the right address, change it to a higher ranked XP