Small Engines (Lawn Mowers, etc.): troubleshoot my lt2000 tractor, mower dies

Question
Tractor is 2 years old, it is craftsman lt2000 17.5 hoursepower 42" cut. Model # 917.28703.  Battery is brand new, fuel filter is brand new, gas is brand new, air filter is brand new.  Starts right up but when I leave off the brake to move it it stalls instantly as well as when I engage the blades.  It runs like new, but I can't go anywhere.  Thanks and hope it is a simple problem for you.

Answer
This should be pretty simple for both of us.  Under the seat is a safety switch that's most likely bad.  It's usually called the operator presence switch and it's job is to shut-off the engine if nobody is in the seat when the mower moves or cuts.

It's P/N 192749 and I have it listed for $10.59.  When you look it up on anybody's parts list, just use that part number on the AYP/Electrolux list.