Most people already know this, but some don't. So i thought i'd share this with mpgh!
Note this is my first post ever on mpgh
I'm not sure if this post is appropriate for this section but if not just let me know
Unfortunately only steam users can do this.
First off, go to your Local Disk (C:>Program Files x86>Steam>Steamapps>common>Call of Duty Modern Warfare 2>Players
Once in the players file delete all .stat files, make sure not to mess or delete anything else, Then head over to your Local Disk (C: )>Program Files x86>Steam>Steamapps>userdata then delete the only file that should be in there, if you have logged into multiple accounts on your pc then there will be more, just delete all of them. Then go to your steam library then right click Call of Duty Modern Warfare 2 And go to Properties then to Local Files, then you're gonna wanna Verify Integrity of game cache, I'm not 100% sure if this step is mandatory but i always do it anyway, just to make sure.