Back in November I changed the fuel filter on my L3540HST and ran it for a few minutes and shut it off. A few days later we got 10 inches of snow and tried to start it, nothing. Messed around with it for a bit and finally called my mechanic.
Took him a while after trying to bleed it etc and finally found out that my fuel pump failed at the same time I changed the fuel filter.
Crazy things can happen.