XPS 15 / 9530 i7 4712 Will not POST (boot) anymore after trying to solve sleep / suspend issue.

Hi, I'm new to this forum. Just got a XPS 15 in the mail and have been following the forums here to set it up.

I got the hybrid model with the 32 GB mSata and 1 TB HDD after reading this article:

Dell XPS 15 (9530) Flawed mSATA Setup

I'm very happy with the computer case, but the HDD was super slow after switching to AHCI in favor of the Rappid start an 16 GB of RAM for the mSATA. (I was going to install a 512 GB SDD instead so this is going off topic)

After setting up the computer the way I wanted I closed the lid and and made some dinner, happy with the computer (apart form the bower connector being very unsafe compared to other modern computers (Mac / Surface etc.)

1. When returning to the computer it wouldn't come to life at all. I was confused, but tried to hold the powerbutton for a little while and then press it again. Sure enough, it had stopped responding in sleep and would need be restarted.

2. The next thing I tried was obviously to click start-power-sleep to see if i was something with the lid. But it remained dead regardless.

I went through 1 & 2 several times eventually concluding with a missing hibernation partition for Intel Rapid Start (It was grayed out & disabled in BIOS) so it became a priority to fix it. So I eventually did but to no avail; computer did not boot a lot faster.

After installing the SSD (Samsung 850 Pro) the computer booted so fast that I actually felt tricked to believe it did sleep and wake up (or at least wake from hibernation.) But then I realized that all the applications I had running hadn't started, so that couldn't be the case.

At this point 2 days of work had passed and I decided to try to set up Ubuntu on the remaining 12 GBs of space on the mSATA.

Not installing anything in particular to my Ubuntu immediately closed the lid and opened it again. watching as the computer just went into sleep and never woke up regardless of how many times i tapped the powerbutton or flipping the lid open. (tried this a few cycles as well.)

My conclusion then was that this had nothing to do with the operating systems, but whit how the BIOS was set to deal with a sleep/suspend request. Sadly I would never be able to figure this out without hacking my BIOS as the power settings tab is hidden in Dell's BIOS (at least in this model.)

When I woke up today I went at it a bit more. (Wasting my entire Sunday.) First I tried to figure out how to reset the CMOS on this laptop, which was not documented anywhere, at  a point where I gave up and started with trying other things. Based on some other thread I tried to disable some USB HID devices, but that didn't help.

I even tried to flash back to the A01 BIOS, but it din't  change anything, so I flashed back to the A06.

The last thing I did on the computer before it got to the state it is in now, ( Not even showing the Dell Logo, just turning the power led on for 1-2 secs then shutting back down. AKA not starting the POST ) was to go into the BIOS And disable any feature that was ticked with "Enabled". That includes disabling visualization, not a good idea, but it shouldn't make the computer not POST. (Idea was to enable one feature at a time if there were a culprit) 

After the last few tests: Disconnecting memory, battery, mSATA & HDD and holding the power button for 30 sec. wouldn't help either. Even tried booting without these devices connected (only AC) and the computer does the same 1-2 sec led light thing as it did whit them plugged in. My conclusion is that the motherboard was faulty and actually switching the settings in the BIOS put it into a different state in witch it wouldn't boot (start POST) at all. I also eventually fond the connector to the CMOS battery (Dell's hidden it well on this and you will have to dissemble a lot to get to the actual battery. luckily the plug is on the topside of the motherboard.)

I let it stay disconnected for a few minutes and held the power button to discharge the motherboard. This had no apparent effect on POST.

I would imagine this could be covered by warranty, but since it is Sunday and i can't call support for another 10 hours, I wanted to start a thread here for others and to document the process. Hopefully Dell tech support in Norway is fantastic. Anyway there might also be a chance that I have overlooked something and can get the system running again without physical assistance, and that would be nice.

I also wan't to add that I have run the Diagnostics and they are similar to my MB Pro which also had a faulty motherboard after two years. The diagnostics would show that nothing was wrong, but Apple concluded with a faulty motherboard after having it looked at. (The behavior before the computer not starting was however a little bit different, but the end result of not going past POST is the same.)

I don't have any experience with Dell support, but I hope I don't have to personally organize shipping within my time of warranty. Also whit the way I'm intending to set up the system (replacing the HDD and reformatting the mSATA) it would be a lot more practical if I would get a shell shipped without  HDD and mSATA installed and thereby be able to move the drives over and send the bad unit back. I don't know if the service with Dell is in that level, but I could only hope. At the very least people should be able to remove the HDD from the machine before sending it, in terms of keeping information secure etc.