Thank you for your question and I understand your concern.
Based on your details I assume you have already located the fuse. The ceramic fuse could be blown. Since it's ceramic you can't see if it's blown so you would have to test the fuse for continuity with an Ohm meter or just replace it and see if will power up.
NOTE: I do not recommend attempting to diagnose and repair your microwave if replacing the fuse does not resolve the failure.
NOTE: I am sorry, but we do not give repair information on microwave ovens because they are inherently dangerous to service.
Microwaves contain high voltage internal components that can retain a lethal electrical charge even when the microwave is completely unplugged. Door repairs and adjustments, even minor ones, can cause microwave leakage, and a microwave shielding leakage test must be performed using a survey meter after any microwave service. That's why I strongly warn you to have this repair handled only by a qualified service technician. You can schedule service online with Sears Home Services or by calling 1-800-4-MY-HOME.
Normally at ManageMyLife.com we like to help you with all of your repairs, but our expert advice is that microwaves are just too dangerous.