GFCIs or GFCI circuit breakers. Look in the circuit box for a GFCI circuit breaker and in bathrooms, kitchens and laundry rooms for GFCI outlets. Test and reset them. This may solve your problem. “I replaced the lightbulb but the light fixture still doesn’t work.” Are you sure the new bulb is good? Try it in another light fixture and make sure it’s screwed all the way in.
“This outlet used to work. Now it’s dead.” Check all the switches in the room. One of them might control the outlet.
