Brannew Just out of the BOX mower, worked... Now Wont Start?!?! Any help...

Just bought a bran-new (( Just Out of the BOX ))

CRAFTSMAN Rotary Lawn Mower

725 Series Briggs & Stratton Engine

Power-Propelled, All Wheel Drive

22' Multi-Cut



Model No. 917.370890

Got it outta the box, Put the OIL in, and new gas, in a New Gas Can bought from the store today....

Mowed half of the yard, and went to put more gas into it --

Now it WILL NOT CUT OVER?....

Pulled it and it wont crank... Any help is very appreciated! Thank You dearly