Why won't my car start?

Triple check battery connections, classic symptoms. Check the cables from the battery to the block and to the starter. Clean the ground under carpet on passenger side tranny hump, 1 screw. Also, check the megafuse right i front of fuse box, has 2 bolts holding it in. Lastly, could be your ignition switch.

I'm not a mechanic but same happen to me last week it had a fuse blown it's located under the hood when you open that box there's different colors the first two are blue there's a 40 the second blue had to do with it it's had to get out . My envoy was like dead but will not let me get the keys out the fuse is blue square shape glasson top.