2006 Trailblazer key will not turn to start vehicle?

Looked into it a little. Seems that the main cause of the problem is that the steering wheel lock is applying pressure and not allowing the key to turn. A bunch of sites say pull hard on the wheel to the left and right and see if it unlocks it, the steering wheel lock could be broken. This is what a GM site said: "Many GM vehicles (and potentially others) have a steering wheel lock that will lock the ignition key. Simply turning the steering wheel in either direction will fix this. " Hope that helps.

I have had the same problem before with my Trailblazer. The problem with mine was that the key would turn to the "On" position but not start the vehicle. The key would then be locked in that position and wouldn't turn off. The problem was that one of the battery cables wasn't tight and there was a loss of power that was preventing the key from being removed. By simply twisting the cable for better contact with the battery terminal the power was restored and the key was unlocked to be removed or to start the vehicle. Ultimately the battery cable needed to be tightened.

the reason it is stuck and is in park and you cannot move the gears is because it has an anti-theft system. Check your battery. Once the battery is charged, the key will come out. Get your battery checked to see if it is good, might need new one. My 2006 also did the same thing.