Dear all, I got a query today, my laptop is black screen and not turning on when I am connecting it to adapter and press power button, it turn on for about 2 seconds with black screen and turn off again then it turn on by itself again and turn off immediately after a voice of beep and blink and it’s repeatedly going on.

 

I removed RAM and checked and the same CMOS battery and HDD but none of them bring changes while removing or connecting.

I also pressed power button for 20 seconds and checked even without battery but its the same.

 

I need your help.

Model: Dell Latitude e7440