First off, don't double-post. I will delete your other one as a dupe.
And to answer your question, if it is power-dead, then no. The system cannot boot without detecting a DVD drive in the system. If it still powered up and spun but had a dead laser, that would be enough for you to boot the system to run the games off of USB.
But in your case, the system wouldn't be able to boot up, if I understand how the Wii works, correctly.