Electricity out in part of house...not circuit breaker or GFCI

The electricity in my kitchen, bathroom, washing machine, dishwasher, dryer and thermostat for heat are all out. the circuit breaker is fine. the odd thing is, when i moved into this house, i noticed there was a light switch in the upstairs, that seems to control nothing. if this switch was turned to the off position, all the same outlets that are out now, would shut off. i have tried resetting the circuits in the basement, nothing has changed. once in the last week, the power turned on by itself and stayed on for about a day....but it has gone out again. should i get an electrician, or is there maybe something i can check first? (oh, and none of the GFCIs need to be reset as far as i can tell).

If you have never done rewiring before, I would suggest getting a certified electrician to sort it out for you.

Hope this helps,
Tigertamer

ph yeah, im not doing any rewiring. i was just wondering if someone here might have an idea for me to check something other than what i have already checked. the only thing i do for electric "work" is check the circuit breaker....
does it sound odd that all of those things are linked together somehow?

Are all these failing circuits on one bank in the fuse box, left and right.
You can tighten the thick input wire/cable terminal screws the ones way on top.
Use an insulated screwdriver.

Sounds like maybe there may have been a separate circuit for upstairs (may have been 2 separate apartments at one stage)?
Check to see if there's another smaller fuseboard somewhere upstairs as I'd imagine this has tripped.Although it wouldn't have reset itself as happened last week..?

First off be careful. There is likely a loose connection somewhere. If the house is older anything is possible as far as how it is wired. One thing you can try is just wiggle some of the switches and outlets that are off. If it comes back up you have found the short. Whatever the case I would get it taken care of pronto.

thanks for all the responses everyone. i got an electrician who ended up replacing the whole circuit breaker. apparently it was old, and the other connections looked like they were on their way out too! thanks again.