My central air when cut on makes a buzzing noise and no air is flowing. I checked the fan and it is blowing. ANy ideas? Please help? Thanks

Sounds like a problem with the blower motor, its relay, or the motor start capacitor. The relay will be a little square box either near the motor, or on a control board for the furnace. The capacitor likely has a cross section with rounded sides and 2 wires going to it. Use a plastic handled screw driver to short the 2 wires together. If it sparks, it is fine. Otherwise, remove the wires, and check it with a ohmmeter. If it shows a low resistance at first, but quickly goes to the end of the scale, it is fine. Otherwise, remove it and take it to an electrical supply house, and let them match it.