I have a nine year old Pony and just a couple of weeks ago, my mower decided it would not start.  The engine turns once or twice, then stops.  It doesn't turn over.  I replaced the spark plug and battery but no change.  I cleaned the air filter and no change.  I am not super knowledgable in small engine repair but want to try to fix this myself if at all possible.  What should I do next?