Latitude D830 crashes; probably battery problems.

Hi.

I've had my Dell for about two years now and recently had to get a new AC adapter and battery.

My problem: Everything's working fine and dandy, then when the battery gets around 70% (not attached to the adapter), it pings, crashes, and dies. It won't turn on again unless it's plugged in, and the LED lights on the battery itself go up to three.

Any and all help will be welcome.

:D