White Macbook battery not charging

I accidently left my charger cable attached to my Macbook with the charger not plugged in. The battery at the time had a full charge. Well, two weeks later I attempted to fire up the laptop. Well, it looks as if the battery completely drained itself. Attempted to charge the batter. Macbook powers up, but "not charging' is displayed. Oh, green light is indicating the battery is charged.

So, do I need a new battery? Or is there a way to reset the battery's memory?

Thanks in advance.