My first thoughts/questions:
Is this true both when plugged in and when no plugged in to shore power? Have you tested your batteries? Have you looked in the battery compartment to see if the battery isolation switches are thrown (shouldn't affect AC, though)? Has some maintenance work been done on your rig in the last two weeks? What voltage readings do you get on the battery terminals? Do you have a "surge protector" that has shut off power?
Perhaps you have both dead batteries and an automatic transfer switch that has gone bad?