(I 2x posted so the OP could see the answer as well.) Yep, I know this is a year later, but yes, I had this same problem. I had to replace the battery to fix it. The "new" battery lasted about a year before doing the same thing. All you can get now are 3rd-party or salvaged batteries for it.
Excellent guide! I used it to replace the screen on my 8440p; everything went according to the instructions, it took me about 35 mins. or so.