iPad will not turn on or charge

I have an iPad 3rd Generation and when I tried to update to iOS 8 it just stopped. The ipad charge logo shows up and I plugged it in and now the battery logo will show for a few seconds and then go away. Then the apple logo will show up and then it will go away. It loops back around and around. How do i fix this? It won't talk to the computer, because the battery is to low.