My 1997 polaris xpress 400 has lost all electrical power.  No starter, lights, etc.  Battery is good.  Looking at the wiring diagram, it looks like it may be the 20A circuit breaker.  I found it, sealed in a bag, but can't figure out how to reset it.  Is it auto-reseting?  Any ideas what else might be the problem.  Checked the ignition switch and it is good.  

more importantly is why it tripped the 20 a circuit breaker.

you could reset but it sounds like until you figure out why it's going to trip again.

polaris has a recall on some of it's machines for faulty cdi boxes, ones that can eventually cause fire and injury.
you might want to look into the recalls to see if your atv is included in this recall.

just do a google search on "polaris recalls"  

Doesn't look like the '97 400 xpress is included in any recalls.  Would like to reset it and see what happens.  Do you know how?  

if it has a reset i believe it should be somewhere in that plastic pocket.

other atv's have them under the rear fender.
for example: suzuki normally puts theirs under the right rear fender.
also check any and all fuses and all connections in the harness to be sure nothing is loose or filled with dirt.