How can I fix my Yardman 6.5 XL, 21 cut, lawn mower? Full with new gas, oil?

Yardman 6.5 XL, 21 cut, lawn mower? Full with new gas, oil, and filter, spark plug- parts cleaned. Tried testing for sparks from engine but got nothing. Does anyone know what else could be wrong? It started last two times after taking it apart and cleaning everything suggested, but now I can prep and try pulling it to start a hundred times, and still nothing! Please help?! Thanks!