If you are using AlterIWnet based Call of Duty: MW2 then you will notice that even though Xfire detects you are playing MW2, it is still not enabled inside the game. The reason is that AlterIWnet uses iw4mp.exe to launch the game but their own custom exe is actually called iw4mp.dat which is actually displaying the game. thus xfire overlays are trying to work on iw4mp.exe and not on iw4mp.dat. There are two ways to fix this - @ Official Site