I had not used my Kindle2 in about a month. I went to use it and was greeted with the dreaded "your battery is CRITICAL" error. Plugged it in and it never charges. Charging light never comes on. I've never run my kindle down more than half battery before. But this time I left my wireless on and totally killed it. Tried all the hold switch down for 30 seconds wait till the screen flashes and plug it in and other assorted tricks from the internet but nothing worked. My guess was the battery on my 20 month old Kindle2 was just plain old dead, or at least drained down so much so that the charging circuitry would not charge the battery. Being the curious sort I pulled my kindle apart. It was actually super simple with the right tools which I happened to have. I took the battery out and put the volt meter on it. It was reading 0 volts. I took an old USB charger and cut the tip off of it to expose the bare wires. I put the bare + lead right against the + battery terminal and put the bare - lead right against the - battery terminal. I left it like that for about 30 minutes and came back and check the voltage. I was up to 3 volts on the battery. After that I put everything back together. Plugged my kindle in and it started charging. A couple of hours later my kindle was fully charged and working perfectly like nothing happened. My guess is that the charging circuitry on the Kindle doesn't activate if the voltage is too low. Pulling the battery out and bumping it up a couple of volts was all it needed to start working again. That's been about a month since I've done that and it's working just like it did before the critical battery error. Might be worth a shot if you have the tools and a spare USB charger you can sacrifice.