While heating a cup of water, the microware died. The front panel is dark, the light doesn't come on when you open the door. The top of the inside compartment was hot to the touch. We have unplugged the microware. Any ideas or is it DOA?

Is it actually heating or just making noise and acting like it's heating? (put a cup of water inside and close the door.) IF it's actually heating, then you have a shorted relay on the main control board, and you will have to replace the board. IF it's just making noise like it's working, but it's not heating, then the problem is 1 of the door switches is not working right (it's either stuck open or stuck closed).

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I'd check to make sure you don't have a door switch that isn't functioning properly. Also, might be a control panel or control panel interface issue.

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Possible that the lock was broken and so the door opened. You can remove the front panel and check for broken plastic or nylon pieces which can be glued using instant adhesive.
Reset the lock and switch and the door must lock in correctly

I just had the same problem with my microwave. First DISCONNECT THE POWER. Remove the front top grill (screws are on top of microwave). Unscrew the one screw at the top of the control panel and lift it out of the way. You will see three micro switches to the left of the pannel. I bent the metal frame they were mounted to by hand to move them back into place. The microwave oven works great now. If this does not help, then I would consider replacing the top limit switch.

1 the obvious question.... have you tried a known working outlet. 2. Most likely the internal fuse has failed and must be replaced. You can access this fuse by removing 4 side panel screws, (2 on each side) and 6 rear chassis cover screws. BEFORE you start unplug the unit. Remove the 10 screws. Standing behind the unit, then lift the top cover slightly and pull toward you. the side guide tabs wil unlock and the cover will come free. Once the chassis open aviod the large capacitor as it can still ruin your day. Follow the power cord until you see the fuse block. Remove the fuse... obtain an EQUAL value replacement and install the new fuse. reinstall the cover making sure the side guide tabs interlock on the front sides of the chassis. Plug the unit in and see if you have any signs of power.... I.e light on with door open or control panel dispaly lights up. If you have visible signs of power places a coffee cup filled with water inside the microwave and see it it heats up. If it starts and then all the power goes off again you probably have a bad diode. If it works fine then your in luck.

I have a Kenmore with similar issues.
Model 665.61639100
Anyway, good luck with this. Hope someone has an answer for you (and me).
Mine has a open slot on the top front of the door. Kinda like a double plate window execpt for the opening in front. Why is this there? I don't know. Weird design. But it leaves for the possibilty of liquid to splash in there leaving it hard to clean (like impossible).

I'm thinking I have to completely remove and disect the door.

It's one or more of the following items -

Fuse
Diode
Capacitor
Transformer
Magnetron

Yes, you can fix the unit, and I can give you direction, but make sure the microwave circuit is not covered under a longer term warranty.

1 take the front grill off. 2. you will see a cover with one screw around the area of the light. normally this is right in front.

check door switches and control circuit.