It happened twice to me too a week ago. Two ways: first try uninstalling and reinstalling the game, the process won't delete any data of your corrupted profile that the game can't see anymore. When you start the game - again- for the first time, your profile and everything should be in place. Second option: If you look into your Saved Games directory under Documents, etc you should find the Crysis2 directory related to your profile - the one that the game now doesn't see anymore - with all your XPs, progressions, checkpoints, etc. I renamed the old profile dir. Made a new profile in the game, and renamed like the old one, then I moved all that was into the old profile dir to the new one, after that I deleted the old one, rebooted and the game saw it again. Sorry it looks a bit dense, I hope this makes sense to you.
I don't have better suggestions, but hope this will help you.