So you mean is doesn't run when you plug it in? Are you sure the impeller
isn't jammed with something? Does it hum or get warm when plugged in?
Stone cold means it probably is dead.

I'm going to check this out this weekend. I just called their 1-800
number that was provided by someone else in this thread and learned
that you can actually remove this yourself and clean it out. The lady
I spoke with said they actually recommend doing this occasionally just
to keep things clean. I had no idea that anything on a pump had a
user-servicable design - I thought it was all sealed up - so I'm going
to try this out this weekend. She also made a mention to hard water
slowly building deposits that could interfere, and I have very hard
water so this is quite possible.