I have a Sony VAIO laptop that is a little over 3 years old. The charger is constantly plugged in, but the computer shut off several times because the battery "died". I got a brand new battery, tried a different charger, changed the battery settings, and the problem is getting worse. Recently it's stayed around 78%, which I guess is "normal". However, today it's shut off four times because there was not battery power left, even though it was supposedly "charging". It's currently at 12%.
Why is it doing this?