EVERY PART OF THE MICROWAVE STOPPED WORKING

Check the timer the switch may be out

Maybe time for a new one. But just in case check the power outlet still has power and the circuit breaker is not tripped.

Verify 15 or 20 amp fuse is good use a multimeter check continuity if no meter replace fuse to rule out it's got to be a power problem.

1= reset the c.breaker from your home see if are tripped and reset.
2= open for thermal fuse open, test continuity with DVOM OR VOM and replace.
3) test the power cord for open or broken or break.
4= check the switch for door maybe is open must be continuity until 0 , or swtich defective see the diagram attached. God bless you

Sounds like a blown fuse. Carefully remove the cover, and the fuse in directly behind the power cord on the top. Radioshack sells 15A ceramic replacements.

cavity therm is bad probably, some people use the micro as a timer thinking they are using the kitchen timer and it burns out the cavity therm. get a qualified svc company to replace the therm, if it is the therm it wont heat or start or anything, if its just the timer thats not working then i suggest a new clock board.

check fuse

I had a similar problem with my Whirlpool microwave. I replaced a fuse (after reading posts in this forum) and it's working again.  I'm not sure how similar your model is, but in my case it was an in-line fuse in a wire leading down from the main fuse in the upper right corner behind the control panel.

Mine went dead after about 6 months. I had problems with my breakers and I found out that it was the microwave that blew all of them. I also found out that this perticular microwave is a fire hazard and should be recalled. It has caused me alot of headache. The breakers in my house are brand new and they are put out by GE also. It caused me to loose the food in my freezer, I did not know my freezer had lost power. It would cause my entire lights to go off and then they would come back on. I have checked around and I found out that the power cord on the back of the unit is very loose. I had a person to come in and look at it, he thinks its the power cord.