new breaker will not reset

I have a 40 amp breaker that suppplied only
my oven, it would not reset so i purchased a
new one and am having same problem.
Any advice other than calling an electrician?

Sounds like you got a short. Have you ever messed with the oven receptical. If yes, chances are the ground(bare copper wire) is coming in contact with one of the power terminals on the receptical. They can be a bit of a pain but if this is the problem, with the breacker OFF of course, take off the receptical and turn it so as when its pushed back into box the ground wire won't touch anything other than the box itself(which will be fine). Also check for exposed wire on the other 3 wires(black,white,red) White being neutral will be opposite the ground. Red and black across from each other.