how do I get my car to start the k is inthe the swictch but wont turn

You say you have the key in the ignition, and can't get it to turn. one of two things, either the key or the key Switch. as you slide the key into the switch, of course it depresses the tumblers, in the key cylinder, then of course, it should turn from lock to run, then to start. either the key itself is worn enough that it is not pushing all the tumblers, in far enough to allow the key to disengage the Locking pins, in the cylinder, or the key Switch is bad. If your steering is locked, try moving it back and forth as you push in and lift up on the key as you try to turn it to on. if your car has a factory security system, be sure to depress your brake pedal. It wiggling the key and steering wheel, together doesn't unlock the switch, it is probably the key switch that has gone bad. very easy to fix. expose, the key switch, and slide the key in all the way. you will notice a small slot under the key on the actual switch housing, use a straighten out paper clip. and with the key fully in push the paperclip end into that slot. all the way. you will feel it release the cylinder, and remove the key and cylinder should slide right out. take the new cylinder, insert the key in it all the way and aline the cylinder with the slot. slide the cylinder all the way in you will feel it click when the cylinder locks into place.

Sometimes the lock on the steering wheel will interfere and you have to wiggle the wheel while trying to turn the key. Good luck!!

?? I have 2002 S500 and my key stopped or want turn, yet my steering wheel is unlocked and stayed unlocked, what was your solution to fixing the issue?