1995 Pontiac Transport Power Windows?

I have a 1995 Pontiac Transport that just yesterday both of the power windows stopped working. I put the windows down after starting it up to go to work, about 20 minutes later I tried to put the windows up and they no longer work. That night I got a new 30 amp circuit breaker and replaced the old one, still the windows don't operate. Other than the circuit breaker what can cause both of the windows not to work?

Mike Petrarca
October 2006