My HP dv6000 laptop will not run on battery power. It will only run while plugged into the wall. I have already replaced the battery, but it still will not operate on battery power.

The problem began slowly. The original battery's life got shorter and shorter, until eventually it would only last ~45 seconds before going into hibernation. Finally, the battery would not work at all, so I threw it out and just used it without a battery. I bought a replacement recently.... but the problem persists.

When I connect the new battery to the system, the "charging" light turns on for about 30 seconds, then goes dark.

I'm assuming there's something wrong with the internal charging circuitry? If this is the case, how would I go about fixing this, short of buying a new motherboard?

If anyone could give me some assistance in confirming/rejecting my diagnosis I'd be very appreciative! :)