Small Engines (Lawn Mowers, etc.): Murray automatic will not move, drive belts, burning rubber

Question
QUESTION: I have a Murray 17HP 42" cut model number 425303x92b, I was using it and got off, shut off the engine, then when I got back on it and started it, put it in forward, and tried to push the pedal, the pedal will not move, neither will the mower. I have looked at both drive belts and they aren't broken or slipped, what should I look at next?

Thank you in advance.

ANSWER: Is the  parking brake set?  First thing is to identify why the pedal won't move.  Is the pedal broke or is a linkage broke or bent?

Eric

---------- FOLLOW-UP ----------

QUESTION: I checked all the rods and connections and everything looks good, I noticed when the engine is running and if you try to push the pedal, the engine seems strained and if you keep pressure applied to the pedal, the belt starts smoking and you can smell it burning (rubber smell). What should be checked next?
Thank you for all your help.

Answer
Below is another link for the model number you provided.

http://www.ereplacementparts.com/murray-425303x92b-4234-lawn-tractor-parts-c-178

Is this your mower?  

If your mower is an automatic, can you find the trasmission model number?  The model number will be stamped or on a sticker somewhere on the transmission housing.

Eric