My heat pump AC failed, but the weather cooled off... When a friend looked at it the heat pump stopped working! Is there something that I can check or replace easily? It's getting cold now!

Reset your breakers... check yourfuses if they have fuses... (my A/C for instance has both)... if your Thermostat has batteries replace them... if none of these solve the problem you have to hire a HVAC pro to check it out.