When I switched on the vanity light in the upstairs bath it failed to turn on. I tried the shower light and the ventilation fan, neither functioned. I plugged a lamp into the GFIC wall outlet in the bath, no power. I tried reseting the GFIC, still no power. I checked the power distribution panel for a tripped circuit breaker, none was tripped. I noted from chart on inside of panel that power to upstairs bath was controlled by breaker in location 20. At this point I called an electrician. He replaced the circuit breaker in location 20 (no effect). He replaced the switches that operated the vanity lights, shower light, and ventilation fan. All connections in the 3 gang swith box were checked and tightened. He also replaced the GFIC outlet. Power to the upstairs bathroom was restored. Two weeks later the problem has reocurred. What can I do now? The house is a 22 year old Cape Cod style. Electrician is talking about having to cut holes in drywall.