My 2000 sportsman 500 will not start off the push button and the lights will not work, and it is overheating which is something it has never done. Any clues as to what might be wrong  

I would check your wiring first being that your having the light issue and the start issue.

Does the starter turn over when you use the push button?  

Starter will not turn over at all. Someone mentioned to me about a fuse up under the front headlamp, but I can't find one. Any idea where it or they might be?  

For the owners manual click here

If you look on the last page I believe that is where the wiring diagram is.

There are several fuses, including a circuit breaker right off the starter solenoid.

Get yourself a Multi-Meter and place it Ohms scale. Use it to figure out where the fuse is blown.

Hope this helps you    

Have you found your problem yet?  I have a 2004.5 Sportsman 500H.O. and I have a problem with mine not starteing with the ignition switch.  I also have to pull start mine.  I switched out my ignition and checked my wires and connot find the problem.  I also just started having a problem with it overheating.  I checked my thermostat and my impellor and both were fine.  Any ideas?  

that should be easy to fix. change your battery mine did the same thing...check all fuses..turn the ignition key with the head lights on....if they dim the battery is dead...replace then check the starter or solnoid..replace and you should be back in business