Bit locker

Impossible if you lost the key and you lost the key recovery you are basically SOL you can try hacking tools such as Backtrack or Hirens but even then you have a 0.0001% chance of unlocking the drive. Had it happen to one of mine when I got drunk one night and assigned a weird password lost everything

You find someone with a quantum computer and do a brute force crack.

this is a good idea, if all else fails use a hammer.

i'm sure microsoft has a backdoor, just ask pleeeeeease.....

and in the future use truecrypt, at you can rest assured if you can get in then noone can (in the next couple decades at least)

No, there are no back doors. Lose the PIN and recovery key, lose the data forever. And for those that think it can be brute forced, Bitlocker's input routine only accepts a new key attempt once per second so it's gonna take a LONG time, even if you had a list of all possible keys.

I was being a facetious ... sort of...