Nothing works on my microwave

One minute my Kenmore microwave worked fine and then a few minutes later, nothing whatsoever worked--the clock was out, none of the buttons worked, there was no light inside. I can open the door, but that's it. The micro. is only 3 years old and was in excellent condition--clean as a whistle. It just suddenly died. Naturally, it's out of warranty. I've tried plugging other things into the same electrical outlet and they work fine. I moved the micro. to a new outlet that I know works and still nothing. Sears wants $30 just to diagnose the problem and I'd have to take it in and pick it up at some distance from where I live (or else they charge $70 to come to the house--exactly what the micro. cost on sale). It seems like it would only take one simple thing to fix it, but I'm wary of opening it up myself--I've read that one has to "discharge the capacitor" and I am an amateur afraid of electrocution! Based on some research, I wonder if it'ss an internal fuse. But I'I hate to get rid of such a "young" microwave--adding to e-waste. My previous Quasar microwave lasted about 12 years. Any ideas? Is it worth fixing or should I just buy a new one for $50-120 dollars (depending on size, etc.)? I'm pretty sure I don't want to buy another Kenmore after this one gave out so soon.