My Lenovo T450 laptop would not turn on, I removed the external battery, then I disconnected the internal battery, followed by that I disconnected the battery from its connector for 10 seconds and put everything back in its place. That worked
Forum Lenovo
cơ bản là, tháo pin ngoài, rồi tháo pin trong, rồi gắn lại (?).
https://forums.lenovo.com/t5/ThinkP.../T440s-not-responding-restarting/td-p/1497468
This helped me solve my problem. Thanks! the key was to remove the battery and AC adapter then hit the reset button. I put the battery back in and it booted up just fine.