Hello,
I have a John Deere GT 245. I was cutting grass this weekend and the blades suddenly stopped working. The button to engage the blades was pulled. I depressed the button and pulled it again with no success. Thinking it may be a bad button, I left the button and raised off the seat, the mower out off.

Hi,
I gather you mean the engine died? That is as it should be if the parking brake was off. Called "operator presence."
Could be a bad PTO switch, a common failure; a blown fuse, less likely than you would think; a broken wire to the clutch, a common problem and found inside the right side frame; or a bad PTO clutch, more common than most think and with Deere less expensive than most would think.
Peace,
Clarke