m15 R6, stopped turning on

Test with a known working power adapter first.

@Chino de Oro​ tried that, did not start

Removed AC adapter, disconnect or remove battery.  Press and hold power button for 30 seconds to reset hardware.  Reconnect power and test again.

Or, check compatibility and performing an RTC reset to recover your Dell laptop https://www.dell.com/support/kbdoc/en-us/000125880/how-to-reset-real-time-clock-rtc-to-recover-your-dell-portable-system

There is a method for BIOS recovery but that will require sign of life (power) of the device.  When all else failed, the issue is with system board, it's toasted.

@Chino de Oro​ tried that too still, it's not working 

Forgot to mention but replace the DC in power jack to see if it could be the issue.

<Do not start multiple threads for the same issue. Merged this to your original thread. DELL-Admin>

2 weeks ago my Alienware m15 R6 laptop stopped from turning on, on this forum I Posted the problem and I was suggested to disconnect the battery and hold the power button for 2 min and then reconnect and try turning it on after connecting the power supply. I checked my power supply, to see if it works or not and my power supply was ok. But the laptop still didn't turn on. Today after 1 week I again pressed the power button on my laptop just to see if it worked and it turned on and it did. Immediately. I connected it to power supply. The laptop showed me a white screen where it was written that laptop memory changed. And it gave me option for bios setup and diagnostic centre. I clicked diagnostic tab and it showed check cable, trackpad and so on. While running advanced test , when the test progress was at 70 percent my laptop shut down and wouldn't start on. I disconnected the battery and held the power button for 2 min and tried to turn it on. It still showed no response. Plz help

Do a battery unseat then 30 sec power drain, then reseat and immediately switch on hibernation mode in the UEFI/BIOS settings. It's caused by the laptop booting from sleep with power plugged in then failing the firmware update (which bricks the laptop).