Battery

if you did keep the lappy on the charger all the time with the batt still pluged in it will wear the batt down...Yes even if you never ran off the batt...they lose power and recharge even when not being run off of...check the connections though and if you can see any probs (dirt,disscoloration anything) then it could be there. If now try finding a batt store that deals with batts they norm can test and fix em if its only a cell or so that has gone bad other than that run it down till its dead and recharge it to the max and see..