Check voltage on the battery. The battery at full charge is near 12.6 volts. Another thing is corrosion inside the start switch. Spray some dielectric cleaner in it to clean it. First I would try to charge the battery. Put it on a 2 amp charge for about 4 hours or on overnight if it's an automatic charger.

 

4 wheeler

i have already charged the battery, but it still wont start. everything shuts of when i push the starter button up. what about wd40 would that work or what else could i spray in there.

 

What you are describing is the classic symptoms of corrosion. You might check the battery terminals for corrosion between the connections. Take them off and clean both sides of the connections. You might check on down the load path for problems at other connections.

Fred