check fuses first. Fix any that are broken.
Secondly, there is a ton of wiring on these tractors, and some of it is underneath, and partially exposed. So if you're in anything rough-a.k.a anything that the tractor is supposed to be used for-it's entirely possible for a stick or limb or tree or rock, or whatever to get up into the wiring and either damage it, a connector, or the harness itself. Or sometimes even break the switch(es).
Usually it's simple. The L40 series have been great tractors aside from a broken wire or connector here & there. I say simple because the ECU/panel "thinks" that the PTO is on and the clutch is not pushed in. So you need to find out why. Once you find it, it'll start and run like normal.