Lost all power power

There is usually an internal ceramic body fuse inside the microwave. The fuse can blow when the magnatron dies, but can blow for other reasons.

The microwave has voltages in excess of 3000 Volts at the magnetron so be careful.

Chelsey,

For future reference, this type of question goes better under, "home and garden" and then " home electronics".

Unless your microwave is over a million years old, of course. ;-)