02 ES problems

Hi, guys i was riding my 2002 honda rancher 350 2x4 ES all weekend and it was running great. At the end of our trip we were on a small trail just riding around and my atv just lost power completely. I went to start it and the battery went dead. So i tried to pull start it and that didnt work. So i let it sit for a couple minutes and then it fired right up using the electric start which was really weird. So then it was running fine....when i got home it did the same thing..lost power and then it would only start with the pull start. I charged the battery and it seems that my battery keeps getting drained out. When i got it going again with the pull start it ran fine until i went to put it in my shed and then my digital display went blank but the atv was still running and i couldnt change gears the neutral light flashed on and off a little. I have no idea what is wrong with it. If you guys could help me out that would be awesome. sorry i wrote so much
Thanks, Any help is appreciated