I have a 23 year old house. It has a small kitchen and I have a 1300 watt microwave on the counter on a spot where it was most convenient. In the beginning all was well but at some point when I used it it stopped suddenly and the outlet as well as the outlets in my breakfast room and the lamp outside went out. Maybe there was an overload or so? On the circuit breaker I cannot find any breaker that is wrong. They were not marked well, so I tried them all turning them off and on. I tried all the CFCI outlets in my house, (replaced the CFCI outlet outside) but nothing changes. What should I do?

Could be a loose connection or splice, need to check the outlets that are not working, could be at the last working outlet on the circuit.

I had a slightly similar circumstance and followed all the wiring for several days and finally found a gfi that I believe the previous owner had left in place on a joist when he installed a suspended ceiling. This circuit involved the outside outlets also and it appears that the gfi had been placed near the first outside outlet. That hidden gfi of course was tripped.
The guy also left me a duct taped splice in that same ceiling, which connected 3 separate 12/2's. Too much trouble to buy a 2 dollar box and cover.
Point is-don't assume anything-- keep looking.
The coup de gras was the vent for the propane hw htr. All the parts and clamps for that connection had been loosely placed on the correct location but never fitted correctly in and tightened--in a house built in 2002 (I am told that county inspections started about 2 years later).