My kindle is 13 months old so just out of guarantee!! While on holiday it froze, would not turn on would not charge. Eventually I got a charge to work and found all my archived books had disappeared. It then worked for about 1 hour but after I swithed off it was frozen again. I've since managed to get another charge onto the battery and rediscovered my archived books but after using it for 30 minutes and swithching off............ite frozen again. This sounds to me like either a duff battery or an intermittent circuit fault with the power module.
Just informed by a Battery seller that the Kindle 2 must have a S11S01B (Lithium Polymer) to work properly. There are alot of sellers selling S11S01A (Lithium-Ion) for the Kindle2. I bought 2 and they did not charge nor would the Kindle2 work even when plugged in. So be sure to check the number of unit being sold to assure it is S11S01B