2006 Chevy Colorado, can't unlock the doors with the fob or key at all

Nice and handy. Does the FOB do anything. Lights flash? Can you hear the unlock solenoid firing? If not the battery may be dead and that you may have bumped the lock rods in the door up to the key mechanism?? If the battery is dead you can try to slim jim the door open to pop the hood and or work on the inside of the door. You can also pop the hood from out side but this will not be fun.

What's the difference

take it apart again. you forgot to plug something in or you have a frayed or open wire. a frayed wire can also cause you vehicle not to start or fail (like quit) on the road. john