Unless you have had it on a maintainer the parasitic draw will deplete..even running it a few minutes isn't enough to pick it back up. Consider this- it takes almost 18 minutes of running at 3000RPM to replace the energy used just to start it if it takes just two seconds of starter draw..let alone pick it back up from just sitting. And a battery that sits with less then 12.4 volts sulfates and becomes unrecoverable so it's likely the battery is gone but put it on a .75-2amp charger for several days then try it. That's why they must be kept on a maintainer if not used and run for an hour or more every week or two. Otherwise check all the cable connections.