Just think of it this way, that electrical box controls everything, yours might be fine, its really simple to pull that box apart and visually inspect to see if you have a burnt spot.
I would do that and go from there, some companies are a few weeks out.
Most likely what has happened is there is a part in your system drawing too many amps and burnt out a resistor. Alot of the time, you can get the 900.00 guy to come out and its only a .30 cent piece to fix it.
Treat it like a buick, look at it, clean the connections, look for something wrong, if the blower motor and spark are working, thats great. If the gas valve is not putting out gas and it has voltage to it, then the gas valve is bad.
Hopefully you have voltage to it, and its just not working, sometimes just clean the connections, but if you have voltage and its not flowing gas, smack it with a hammer, there is a diaphragm inside that might be not working right.
This is not a propane system right? Standard gas line or what?
On a side note: you do have it set to heat hehe just kidding.