Was the tank full of water? If not, the heating element probably overheated and burnt out. That may be the problem regardless. You said you checked fuses: did you check the 120 VAC breaker for the water heater?
Update, this was found when the tech came to fix the water heater after we tried everything and checked everything we could .He had to pull the heater,which I couldn't do. Funny that it didn't blow a breaker. Glad it didn't start a fire.