Small Engines (Lawn Mowers, etc.): Craftsman Rider wont start, mixed signals, safety switch

Question
Hi Eric,
I thinkt I may have a short in the electrical system. I used the mower for about 5 hours, on and off, to clean up my yard. I turned it off toward the end of the day for about 20 mins to move bags and stuff. When I went to restart, I had nothing. I mean nothing. Turn the key and not a thing. The battery is very new and has a charge. perhaps some connections are dirty or something. When I was shutting it down the last time, the engine ran rough, like the belts where loose and shaking. Perhaps the sensor for the seat was sending mixed signals to shut off the engine because of a short. Is there a way to test for a short? The fuse is intact. I checked all the connections, they appear fine. Could something as simple as dust on a connection cause the rider to not even turn on? I asked John form allexperts.com and he said that he needed my sears model number so he could "Locate a Breakdown/IPL" he was saying that some of these mowers have a relay under the seat that could cause this problem. However, now he's on vacation and I need to get this thing fixed. Any ideas on what I should do. The mower is a Craftsman LT200 rider, model number 917.273764. It has a 18HP OHV Intek B&S Engine. Any help you could give me, would be really appreciated.  

Answer
Lets start by idnetifing the solenoid.  You can locate it by following the positive battery cable.  The first part is goes to is the solenoid.  I need to know if there are 1 or 2 small wires connected to it.  The parts list did not provide a very good picture.

Second, start at the key switch and follow the wire harness to each safety switch.  Yes, dis-connecting and reconnecting them will ususually clean the connection enough if there is dirt or corrosion on the safety switch connector.  I have fixed several mower by doing this.  I have also found broken switches or they may have fallen our of the part holding them in place.

These are the easy things to check.  Do you have a multimeter to do some more trouble shooting?
Let me know.
Eric