Are they the same disk? I made this thread a week ago  http://www.giantbomb.com/battlefield-bad-company-2/61-25246/wont-play-from-hard-drive/35-476788/#7
 I got the game from a friend again and installed it again. It works fine after installation when i use his copy (plays from flash drive not disk) but once i put in my copy of bfbc2 it plays form the disk and not the flash drive.  My copy is limited edition while his is not so im wondering if this difference may be the cause of the problem. 

I don't see why they would be a different disc, but I don't know.

 The disc should have the exact same contents. I was under the impression the limited edition came with a code that gave you the unlocks as the only difference aside from box art.
 
How damaged is your disc? You might end up being able to use a disc buffer and fix your copy. I've been using my Game Doctor for years and it has saved a dozen games I thought were ruined forever. Or at worst, you could rent a copy of the regular version and from install that.