Missing firmware password, can't access boot options
Hi,
I own a Macbook Pro (13") which I bought from Ebay a few months ago. I recently changed my password to my administrator account, but I cannot remember it. I know of several bypasses to this, but as I attempt each one, they all seem blocked by a firmware password. I have tried contacting the original owner, but he does not remember what he set that as. I'm locked out of all boot options and my administrator account, I'm typing this now from the guest account which I enabled a while ago. Solutions?
MacBook Pro, OS X Mountain Lion (10.8.5)