Hi @redxps630 welcome to this free user to user Alienware laptop discussion forum. 

Please disconnect battery. Press and hold the power-on button for 15 seconds to drain laptop flea power (Hard Reset). Laptop without battery is designed to function as Desktop on ac adapter power. Connect ac adapter, does power cord's diagnostic LED remain on, does Alienware 17 R4 power-on? 

Resolve No Power, No POST, No Boot or No Video issues with your Dell Computer | Dell US 

Thank you.  I read the service manual.  It seems pretty hard to remove battery which requires removing a few other things first.  Seems daunting.  I did not expect this much difficulty compared to other Dell laptop model lines.

I took off the base and removed the battery. laptop still has no sign of power.   Power button has no light.  nor is there any other light.  I observed the original AW charger has a blue led at the base of barrel tip when it is plugged in wall and not laptop.  As soon as the barrel is plugged in laptop, the blue led vanishes.  unplugging it does not bring it back.  I need to also plug from wall then plug in wall again to bring back the led.  does this mean the laptop is short circuiting the ac adapter, and the adapter turns itself off?

I verified the charger works in another Dell laptop and its wattage is correctly detected. In the other working laptop, the blue led at the barrel stays on when plugged in laptop.

Hi @redxps630 thank you for sharing update. 

The ac adapter power cord's diagnostic LED and your check that it works on other Dell laptop confirms that the Alienware 17 R4 laptop dc‑in port has a fault. This should be normal wear and fixed by installation of replacement Power Input Jack Plug with Cable DP/N 0K5M1. Search on internet reveals many sellers of this new replacement OEM part. 

Power Input Jack Plug with Cable DP/N 0K5M1

Thank you.  I took this cable out after some trouble (it was secured with tape underneath motherboard).  now when I connect just the DC jack cable to charger, leaving the other end disconnected from motherboard, the charger's blue led stays on.  Does this suggest possible motherboard itself and not the cable that is causing short circuit or fault?

Hi @redxps630 thank you for sharing additional information. 

Your diagnostic check of just the DC jack confirms that this might be good but does not check all of the Power Input Jack Plug with Cable electrical system. Having already dismantled the Alienware 17 R4 laptop and DP/N 0K5M1 is only about $10.00 it is not worth having a debate, example Amazon.com: Rangale DC-in Cable Power Jack Connector for Del-l Alienwar-e 17 R4 Series Laptop 00K5M1 P31E DC30100Y700 : Electronics. 

@redxps630 If the adapter light goes off then the high chance is that you have a short on the board. Very rarely it is related to the DC jack and usually comes from the GPU, but it could be on any board component. 

You can try removing anything you can (RAM, wifi card, storage drives) to see if the light stays on but you're probably up for a new board unfortunately. 

You can also try a power drain but that would be a long shot for this one. 

unfortunately, a new dc jack shows the same problem.  so, there is a short in motherboard.  oh well my first baby alien is a dead one.  only good for parts.

Hi @redxps630 thank you for sharing update. That is disappointing. 

The $100 Dell Laptop Repair | Dell Repair | Laptop Repair | Notebook Service Center (parts-people.com) seems a good option. 

Hi @redxps630 ,

Thats quite terrible in my opinion you have to deal with a short, circuited Motherboard as that's usually rare but that reminds me on how most 17 R4s I've bought have some issue with it, whether it's the LED light blinking red and blue (CPU is Faulty or Mainboard) or Screen flickering. I have fixed these issues in the past but basically the CPU one is just a false positive due to the fact I could turn it on after doing a discharge and the screen one was due to the cable being bent in a certain direction.