so it does nothing? no Fans Spinning, no Lights, no Noise, Nothing?

well  as above any fans anything?  or just complete dead?

the power adapter has either a blue ring were it plugs into the system, or a small green led light on the power brick itself.. is this on? ..

after having my  X51 R3 take a dump early friday morning  , but being under warranty doesn't bother me much, but i did figure out my issue and get it running now just awaiting response(never on weekends) from dell  on how to proceed on replacement parts, or system which eitherway  its gonna be fixed  

if no power light is on adapter.. unplug it from machine.. then from wall for few minutes.. then plug back into wall. NOT the machine  see if it lights up the light on the brick.. if it doesn't  light up then adapter might be toast..  if it does.. plug it into machine.. if the light goes out, motherboard is most likely shot, or the internal dc/dc power board

Once I had a problem of not coming on for a laptop with totally OK power adapter. The only way to identify it is provide such tool to power adapter outlet socket - but make sure you do not shorten poles between each other or your power adapter will surely be cold dead! In my case the power cord after adapter got broken wire inside so even lit lamp could not show that power is not being delivered to PC!

Did you try discharge of power supply by disconnecting ALL cables from ALL ports and holding the power button to discharge.  Then plug ONLY power in and press to turn on.  What about the BIST button?

No Power? Learn about Dell's Built In Self Test for power - YouTube

No POST, No Power, No Video on a Dell Desktop Computer | Dell US 

The computer is a model J6WFNS1. re: first first link of No power?... The

video shows two buttons, of which one engages to reset. Apparently, if

this model supposedly has such, I cannot find it on the back of the PC.

Basically, The power adapter works fine. Plugging it in, the start button

does light up. Nothing else works though. No machinery noises, such as

fans, or the usual noises when the HD starts up. I'm quite sure some

component, or other, has failed. As to what it might be, I don't know.

All I can say is the adapter works, and the start button lights up. Those

are the only two things that do.

Would appreciate your any suggestions you may have. Thanks for listening

you mean the power button light? 

if so sound similar to my current issue..  except my fans reved up,  video card fried..   so either find or vieo card you can test with .. even a cheap one..  or try and boot off the onboard.. after removing  the discrete card..  

I do believe the X51 dosent have these *reset* buttons like some  full desktop version do,  atleast my experience anyway 

you can try a full power dissipation but  unplugging and holding power button for a minute , but I'm sure this has been tried.. 

otherwise its possible the board failed... 

Discrete card? Do you mean the video card?

i'm obviously not him but yes, the Video Card. you might have the same Problem as the Guy in this Thread here:

you can try to do exact the same Stuff he did. he got his PC working after all.

On Wed, Jul 12, 2017 at 5:13 PM, CarbonBasedLifeform

re: video card recommendations to replace the Nvidia CTX 545DE.

Here's the AC Adapter specifications for this computer

Flextronics Model GA240PE1-00

Input: 100-240 Volys (52-60Hz

Output: 19.5 volts

There is no wattage listed on the adapter.

Hope this helps.