✔ 最佳答案
Do you install the battery? If yes but problem still happen, your notebook battery should be dead already. Buy a new battery.
I am using T40 for about 3 years, I un-install the battery if it's not using(working in fixed location).
From time to time, you need to charge it to full for once(about 1-2 months) to keep it alive, else, idle too long, battery will die also. My battery is still under good condition.