I replaced the battery last September and have had NO PROBLEMS.
I've used the mower at least twice a month since March with no trouble and used it 2 weeks ago.
Yesterday I try to start it and the first time it turned over as usual, but did not start.
Second time it did the same.
I waited a few minutes then tried again and all I heard was clicking noises.
The next time I heard the same clicking noises and smoked started coming from under the hood.
Engine is siezed and you are burning up the starter
or
Wires have come loose and creating a direct short
or
Diodes in charging circuit have failed closed and the alternator is burning up.
Open the hood and have a look.
Try to rotate the engine by hand.
No joy, remove the spark plug and try again.