After a while even rechargeable batteries loose the ability to hold a charge. This process accelerates when the battery is allowed to lie completely discharged for long periods of time. NiCad batteries especially have this issue. If you left the battery sitting for long periods without occasionally charging it, it losses the ability to hold a charge. It appears you are going to have to either do without the battery or replace the pack. I would take out the old one, it will eventually start to corrode and leak and if its still in your machine it will cause damage. If you get a new battery pack make sure you charge it fully and then depleat it completely before recharging it. hope this helps.