Hello: The battery might be dying: Try this.
- Connect your BB to the wall charger
- Leave it alone for 2 hours, no matter what the LED or the display does
- Hold the Up/Down volume keys until the device fully shuts down
- Wait 15 minutes
- Try to start the device normally
- Wait another 2 hours, no matter what the LED or the display does
This has been known to "kick start" some BBs. If it fails, please try again but increase the step 4 wait time to 2 hours, and perhaps as long as 4-5 hours. If that still fails, then review the "known good" recommendation for the charger...find another device without issues and ensure that the charger is functioning correctly.