[Saber Cherry]

Wiping a HDD won't erase much. Unfortunately, it probably would be cheaper (and certainly easier) to buy a new copy of Doms II than to recover the contents of the drive.

You should try communicating with Shrapnel. If you can email them a scan of the box juxtaposed with your face, or some similarly silly proof of ownership, they should resend you a key. Legally, in the U.S., an owner who loses his key has the right to a replacement key, free of charge. Unfortunately, the burden of proof rests on the owner... but Shrapnel staff are nice people, so they may cut you some slack.