Dell Latitude E7440 power light on and goes off after 15 seconds
I has a Dell latitude E7440. I face a issue but cannot understand its fault. My dell latitude E7440 running windows 10 does not power on. When power button is pressed, the power light stays on for about 15 sec then it goes back off. Nothing appears on the screen and fan does not run. I have already installed latest bios. Butt problem is not resolve.
For checking it works with CMOS battery Now, i removed CMOS battery permanently and install the main battery first time laptop show message set date and other bios setting but after restart my E7440 start normally not show bios setting set message. Problem also occur as CMOS battery already removed now i reconnect the main battery then PC turns on. i cannot understand its fault.
I also mention the error video from YouTube: https://www.youtube.com/watch?v=tuJ0sIe4...
A humble request, suggest me whats happening. So i can solve it.