Jump start the engine with the battery disconnected. Using a volt meter you should be reading 13 to 18 volts from the positive battery terminal to ground. If that voltage it present the charging system is working and the battery is bad. Also check from the positive terminal to ground with an ohm meter with the engine and key off for a short that could be killing the battery.
Rick, August 2006
Rick, the battery was new but it is now dead and won't hold a charge.