Hello, A few months ago I bought a second hand macbook Pro, a few weeks ago my hard drive failed. I tried to format it and then i tried to install mac os x again from the recovery part of the hard disk. The MBP said he wasn't able to do that because he couldn't de-activate the hard drive. Then I decided to buy a new hard drive because i also wanted an upgrade so I bought a 750GB WD Blue. Replacing it was easy, then I tried to install os x with the recovery disk i got from the guy who sold the MBP but apparently he did something wrong while making the disc because the MBP just couldn't start the installation. Then i tried to do the internet recovery but the guy bought mountain lion with his app store account so I can't use that. Do you have any clue what I can do about this? Or will I just have to go to the store and buy a lion disk? (18 on the online Apple Store) Thanks in advance!