My arctic cat four wheeler's battery and electrical systems don't seem to be working?

my arctic cat four wheeler's batterary and electrical systems dont seem to be working. the lights only work slightly when it's running. and the winch doesn't work at all, niether does the electric start. and no lights or anything when it is not running and the key is in the "on" position. even when the charger is on the batt, the electrical componets dont work. i put a multimeter on the battery and its fine, so are all the fuses. any suggestions?|||Bad grounding wire?