What can be the problem? None of the breakers are tripped. halft of my house has no power. I reset the main breaker but it did not help.
It sounds like one of the two legs feeding your house died. Inside your panel, the slots for the circuit breakers alternate like so (full explanation of circuit breaker panels
Your power company will connect two wires to this box via the meter. Most likely one of the wires has gone bad. In my case, a wire between the transformer (underground) had gone out. They used something called a dry transformer to get us service on both legs until they could repair the damaged wire.