Problem launching MW2.

[Deleted]

Hi there, I recently wiped all the data on my external hard drive, and after I had reinstalled all my stuff, I've had problem launching Modern Warfare 2.
The problem is that the little box saying "Preparing to launch Modern Warfare 2." pops up for about 5 seconds, then disappears for like 2 seconds, and then appears again, and it continues doing that until I exit steam.

I have already deframneted the cache files, so I was wondering if someone could please help me and maybe tell me what to do.

Edit: Just reinstalled the game. Doesn't help either.