Could be a few issue that prevent power to the microwave.
First check that the socket outlet is working that you are using.
Then the fuse in the plug, if these are fine check flex for damage.
If all those are in order, you can assume it is an appliance problem.
There is also a fuse within the microwave, normally placed on the PCB.
These could have also blown, so that is worth investigation as this is quite an easy fix.
A word of warning though, microwaves work be using step up transformers and capacitors, they capacitor stores energy, this can still be stored even when the power is off, so they is still a potential shock hazard, even when the appliance is isolated, this should be earthed to drain the power down.
If it's not the internal fuse, then it could be the magnetron that has packed up. You can replace these yourself or take it to a repair shop. It cost me £30 last time I had one repaired.
If you have a multimeter? I would do some continuity and voltage tests.