Take a plug wire loose at the cap (just a little)and see if you're getting
spark when someone try's to start it.
If you are then loosen the fuel filter and see if you're getting pressure
when starting.
These aren't foolproof ways but if you're not getting any spark you
know you got an ignition problem.
And if you're not getting any fuel, well you need to look at that side.
If both seem fine then you may need a fuel pressure test or
diagnostics on the ignition system, but that's a good place to start.
You could even have some water in the fuel that froze up.
