It may take up to 4 hours to fully charge your Kindle through the power adapter if the battery was completely drained.
I have tried recharging and holding the power switch for 30 seconds. Still remains stuck on Empty Battery screen. Is it possible the battery is dead??
I purchased a new usb cable and checked that the plug and power socket were working ok. Kindle purchased in 2010. I don't have phone charger that would fit the Kindle.