Lawn mower that won't start

Hi
My three year old cratsman LTS 1500 won't start. I have replaced the fuel filters (fuel and oil) and the spark plug, but got no joy.
Any Ideas?
Thanks

I would check to see that it's getting a spark and it's getting fuel first.

To check the spark, just take a piece of wire and run it from the (disconnected) spark plug wire to the engine body. when you crank the motor, you should be able to see a spark.

Check that it's getting fuel by removing the spark plug and cranking a bit. if it's wet in the hole, you're getting gas.

I'd go from there.

Good luck