Here are your parts
Replacement parts for FRIGIDAIRE FEF336FMC Frigidaire/range | AppliancePartsPros.com

Here is a manual which covers many Frigidaire models
http://frigidaireservicetips.com/pdfs/344_UpdateforElectricFreestandingElectricRanges_Rev.pdf

The reason they told you to flip the breaker is that sometimes you can loose half the line without actually tripping the breaker and the elements need the full 240.
Since the stove top elements work OK the unit is getting 240 volts.

If the stove comes ready, it could be that the oven sensor is no good.
The unit then thinks it is at set temperature and never heats up.
If it stays in preheat then this is not your problem.
Note: That most units will give an error message if they see an open sensor but it could be you have a bad connection which adds resistance to the circuit.

Below is a link on how to check the sensor etc.
http://www.applianceaid.com/elecrange.html

Unplug the unit and check for broken/burned out wires.
If everything looks OK then odds are that your control board is shot.

I cannot say if you can fix iot yourself. It is not difficult and most DIYers have no trouble doing it.
Just be sure to always unplug it when working on it.
[COLOR="Red"]240 volts is lethal!!! [/COLOR]