As title, I don't does it is already same topics in here but let me talk again.

When playing single play story mode, the "Melee" function almost (maybe up to 80% chance, not sure) disabled after reload the checkpoint. Just non-function with the Melee key.
- I tried to enter option menu to re-assign another key and it is still no.
- I tried to back to main menu and resume campaign and it is still no. Only can exit the whole game and re run the Crysis2.

But sometimes (not 100% success) I can resume the Melee by try to make a "Press _ for a power kick". Just try to walk to find a car or big box and then do a power kick action, then 50% chance the Melee function will back.

were aware, and there is not fix (YET).