Couple of items here could be the oven sensor, the heating elements, and maybe the relays on the control board, you will need a volt meter to do the proper checks.If you dont feel comfortable working around volts the next best thing would be to get a tech out there to look at it.Im sorry but this isnt a magical repair.
I mentioned that it could be i didnt say it was about the oven sensor. Yes the main control that sits behind the display. Also could be the high limit thermastats also thats why i mentioned to get a technician i dont think it could be the boards like what that other technician said its highly unlikely that 2 of them go out at the same time.
The expert that originally assisted you just entered this again after my reply about the oven control. Please decide which one of us, if any, you want to continue with.