We turned off the main water line to the house for several hours while we bought a new water valve for the refrigerator. We came home installed the new valve, and turned the water back on. There is no water coming into the water line now. Any suggestions?

You should have flushed line before re-attaching it to valve. You probably have trash in line which went to diaphragm. You will have to loosen fittings until you find blockage or dis-assemble valve and get trash out of diaphragm orifices.