I just recently purchased a new macbook without the MAC OS X Install Disks. So, I tried resetting the original username and password while using the recommended "back door" method. It didn't work, now the macbook will not turn on completely. It powers on, but only gets to the white page with the apple. Than it powers off and then goes back to the white page. It will continue doing this but will not turn on all the way. How can I fix this so I can install the new MAC OS X Install Disks? Thanks!