Okay, Two things you can do
Did you configure a Whole Disk Encryption Administrator passphrase in your policy?
If so at the Boot Guard screen User name is WDE Administrator ---- passphrase ----- Domain is This Computer
That would get you past the initial encryption piece.
If you didnt do that you can retrieve the Laptop and take out the hard disk drive and slave it to another PC that is encrypted and use its Whole Disk Encryption Desktoip client to unencrypt or Unlock the DIsk.
If you just want to unlock the DIsk use the pgpWDE cmd line tool, if you want to unencrypt use the Desktop GUI.