Won't start

Well, I turf tiger started right up today then after mowing for about 20 minutes i parked it. I got on it to start it up after about an hour and when I turned the key nothing happened. And yes, brake was, seat was down and I was sitting on it, control levers were out and deck was up. Any ideas. This happened about weeks ago. I have some ideas but would like to get some from you guys.

This is my 5th season with the mower bought brand new.

-bobby

Won't start