When I prees the start button, I hear a click and microwave shuts down. A few minutes later I can get power back and try again and the same thing happens

There might be a problem with door switch for your microwave to be turning off after 3 seconds and the door switch will need replacement on your microwave.

The unit could be overheating and shutting down, cooling off, and restarting. Check ventilation holes on back for dust accumulation and blockage. Check that cooling fan is turning properly.

Not enough venting. Imagine putting your hair dryer on full and putting it that cabinet. Would your venting keep it cool? Your microwave oven uses about the same current

i would check your thermal cut offs inside he cabinet,there is a chance that your cooling fan is bad,even thought it may be turning it might not be turning at a fast enough rpm to proper;y cool the unit.
the last thing that i think would be bad is the control board.I hope this helps you get your microwave fixed

Ours just started doing this exact same thing this past Friday - 12/11/09. What's going on? The cook power just starts beeping all by itself and going from 10 down to 1 over and over again. It may stop momentarily, but then starts again within a minute or so - it's constant until we unplug it. We plug it back in and within a few minutes it starts doing it again. What gives?

I think you've put up with enough hassle from this unit and should get another one. Intermittant flakey problems are hard (read expensive) to fix.

Found this in the GE section instead of Maytag, but we're happy to answer it anyway.

The first thing to try is a "hard reset". Unplug it from the power line for a few minutes, plug it back in, set the clock, then try again.

Let us know if the hard reset doen't fix it.

If not, you may have a shorted keypad or bad control panel, either of which we can repair economically.

Please write back with more details if you need further help.

Assuming the entire power line from the breaker to the microwave cord is okay, it's almost certainly a bad connection on the circuit board of the control panel assembly. For reference, we repair these from all over the country for $32.50 postpaid.