2006 GMC Sierra Denali,wont turn over, battery

IF YOU HAVE NO 'CLICKING' OR ANYTHING THAT INDICATES A DEAD BATTERY - NO DASH LIGHTS ETC, THEN LOOK AT YOUR BATTERY FIRST, TRY TO JUMP IT. THISE ARE TOUGH TO JUMO AND TAKE ALOT OF JUICE TO START YOUR VOLT METER NEEDS TO READ OVER 13 VOLTS, DO NOT CONNECT TO BATTERY FOR BEST RESULTS, CONNET TO ENGINE, NEXT TO THE ALTERNATOR IS A GREAT SPOT, AND THE RED BLOCK THAT IS UNDER THE MASTER BRAKE CYCLINDER (YOU'LL SEE IT WHEN YOUR STANDING AT THE FRONT OF THE TRUCK AND LOOK TO THE RIGHT BETWEEN THE BATTERY AND THE ENGINE)

IF YOU CAN GET ANY JUICE TO THE CAR TO EVEN MAKE THE LIGHTS COME ON AND GET THE INSTUMENTS TO READ OUT, ETC BY USING JUMPER CABLES, THEN MAKE SURE YOU CAN GET JUICE, ALSO MAKE SURE THAT EVERYTHING IS OFF, ROLL DOWN THE DRIVERS WINDOW - OF COURSE YOULL NEED TO MAKE SURE THAT IF THE VEHICLE DOESNT START TO LEAVE THE JUMPER CABLES ON LONG ENOUGHT TO PUT IT BACK UP, AND CLOSE THE DOOR, LEAVING ANY ACCESORIES ON LIKE THE AC, RADIO, ETC JUST MAKES JUMPING THIS 10x HARDER, YOU MIGHT EVEN NEED 2 CARS AND 2 JUMPER CABLE, I THINK THE BEAST NEEDS SOMETHING LIKE 400 AMP TO CRANK OVER, IT'S ON THE BATTERY. ANYWAYS THE REASON WHY YOUR PUTTING THE WINDOW DOWN IS SO YOU DONT LEAVE THE DOOR OPEN AND WASTE JUICE, LEAVE THE KEY IN, BUT JUST PUL IT OUT ENOUGH SO IT'S NOT CHIMING. HAVE THE PERSON WHO IS JUMPING YOU SLOWLY REV THERE ENGINE TO SEND MORE JUCIE TO YOU. I HAVE THE SAME TRUCK AND HAD THIS HAPPENA MILLION TIMES. I FINALLY BOUGHT A JUMPER BOX FOR $50 AND IT SAVED ME ALOT OF HEADACHES. MY PROBLEM WAS I HAD A PROBLEM IN THE ELECTRICAL THAT LEFT A DRAW OPEN - THE IDEA THAT WAS POSTED ABOUT BYPASSING RIGHT TO THE STARTER IS A GREAT ONE, BU IF YOU NOT SURE WHAT YOUR DOING IT'S NOT REALLY THE 1ST AVE I WOULD TAKE, IT WILL JUMP THE TRUCK AND TURN IT OVER (UNLESS THERE IS ANOTHER PROBLEM) BUT WHAT ABOUT THE NEXT TIME? IF YOU PUT THE KEY IN AND GET A READING OF 13 +/- VOLTS ON THE DASH GAUGE THEN YOUR PROBLEM IS MOST LIKELY YOUR SOLINOID (SP) IT'S ABOUT A $60 PART AND EASY TO PUT IN, INVEST THE $$ TO BUY A CHILTONS OF EVEN BETTER A GM SERVICE MANUAL FOR THE TRUCK. WHEN YOU DO GET IT STARTED THE GAUGE SHOULD START TO RISE AND READ 14.5 +/- VOLT CONSISTANTLY, BUT IF YOU GO TO AUTO ZONE THEY WILL 'LOAD TEST' YOUR TRUCK FOR FREE. IF YOU STILL HAVE THE ORIGINAL BATTERY ITS TIME FOR A NEW ONE - AND DONT CHEAP OUT ON THE CHEAPEST ONE, SPEND THE MONEY FOR A GOOD BRAND OF BATTERY, SOMETHING THAT CAN HANDLE THE BEAST, 600 COLD CRANKING AMOS IS WHAT I THINK THE RATING FROM GM IS. IT WILL SAVE YOU A LOT IN THE LONG RUN. AUTO ZONE WILL HOOK UP A TESTER AND LET YOU KNOW IF YOUR BATTERY IS NO GOOD OR YOUR ALT IS BAD, ETC. BUT IT PRETTY MUCH ALLL STARTS WITH THE BATTERY.

THE ONLY OTHER THING IS THAT YOUR VEHICLE MAY BE IN LOCK DOWN IF YOU HAVE A KEY THAT IS WORN REALLY BAD AND ALOT OF MILES YOU MAY NEED TO REPLACE THE IGNITION CYCLINDER - ANOTHER $60.00 FROM THE PARTS COUNTER, AND THEN YOU NEED TO HAVE A BLACKSMITH CODE THE CYCLINDER, $35.00. HOPE I'VE HELPED

Check for loose wire at starter, try to turn motor with bypass at starter.