- A separate charger will work with the added inconvenience - you have to turn off the device in order to charge.
- If you didn't charged for a few days but the battery is "almost" empty than I'm pretty sure the battery is good. When they go bad they don't hold a charge anymore.
- Does it charge when the device is off?
- Borrow and try another charger / your charger on another nokia phone
- Maybe the charger socket went bad? It happened on my e71 and it's pretty much the same one.