Boot SnowLeopard Mac w/Leopard clone?

[ajsedl]

I've been using SuperDuper! for years as my backup methodology, from my main computer (a MacBook Pro) to a LaCie hard drive. It's always worked fine and still does, allows me to boot from either.

BUT--and here's the problem: My only computer, my MacBook Pro had to go in for repairs. They replaced both the optical drive and the logic board. While I was without it (10 days), I tried to use my husband's newer MacBook Pro to boot from my backup on the LaCie drive. It goes into the gray apple mode but then nothing. Doesn't boot. ALL these are running system 10.6.6. What stops the boot from my husband's computer?

Now I learn they have to re-replace the logic board because they put in the wrong processor (they gave me a downgrade in GHz in the first repair!) I need to know how to boot from the LaCie with his MacBook before my one-and-only computer goes away! Thanks for any help.