COD 4 Achievements

I need help with the COD 4 Achievements and the fact that I haven't been getting them. The only "cheat" I've used is the "COD Noir" and I haven't got any with the exception of "4 of a kind" Now I have started a New Game and didn't use cheats but still didn't get any has anyone else had this problem and can anyone help me? I thank you in advance for your cooperation.

Did you try turning the cheat off on your old save (if you didn't delete it, which wouldn't have been such a great idea)?

Are you in arcade mode (which I think disables you from getting achievements)?