The service and the guy said that the various hardware tests didn't report any kind of problems. Later I was told that the deeper diagnostic test reported problem with the audio controller and that's why the logic board needs to be changed! Check with you local service center and see if they have a same issues reported for the audio controller. if that's the case then we all have a faulty MacBook pro that Apple needs to recall!
I hope you guys are you putting this thread to the Apple feedback page over here.
I'm having the same problem on a 2009 MacBook Pro. It randomly freezes, and neither the built-in keayboard and trackpad nor a USB keyboard and mouse work. But the programs seems to be fine - can't really tell tho - this MacBook Pro has always been a little flaky. Now maybe I know why... faulty Logic Board?