engine wont crank

Engine Mechanical problem
2003 GMC Yukon V8 Four Wheel Drive Automatic

car fully powers up electronically, engine does not crank up at all

Are we talking about its cranking over and refuses to start or won't crank at all/nada

Cranking and no start do below:

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine -have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it

No crank/nada:

Could be the battery/connection, alternator,starter, starter relay, park and neutral position switch and ignition switch