Try to use the one time boot menu (F12 key) and see if you can boot from USB installation media.

This way you can rule out drive failure or driver issues.

Well, it is true that I have also installed the BIOS update in the same time with the chipset driver and Intel thunderbolt. After these 3 were installed , I have restarted the computer. It is possible that the MB is bricked? If it is, is there any chance to rewrite/flasg the Bios using a USB stick?

Re: Why this problem appears after installing the chipset driver?

can be coincidental.  the lights can be a clue but may not be 100% reliable.  if your R7 cannot POST at all, no video, then it is not a hdd issue.  I would try to use a spare psu if available to r/o psu failing.  note a test psu needs to have two 4/8 pin cpu/eps connectors, one for mobo cpu, one for mobo gpu_pwr header.  also make sure you replace cmos battery w a brand new one.  you have already tried cmos jumper reset according to your report.  worst case scenario is bad motherboard or corrupted cmos.  hope it is not.

I have tried to boot up pressing f12 + USB  with windows 10, nothing happens. My keyboard lights up, my screen remains black, the power button turns from blue to 3 times amber blinking.( like after 10 seconds after I push the power button)

@Gosdra88 

"3 - 6 amber flash" is bios update failure.

Aurora r7 drivers

Please press the blue Accept as Solution button below if the post answers your question.

Note: BIOS recovery is only applicable to USB 2.0 FAT32 flash drives.  All other storage should be removed to recover bios.

3,6 blink means its not dead yet.

 BIOS RECOVERY

How do I initiate BIOS Recovery on a Dell desktop or all-in-one computer?

1. Restart the computer.
2. Press and hold the CTRL + ESC key on the keyboard until the BIOS Recovery page appears.
3. On the BIOS Recovery screen, select Reset NVRAM (if available) and press the Enter key. Select Disabled and press the Enter key to save the current BIOS settings.
4. Select Recover BIOS and press the Enter key to start the recovery process.

Are you seeing a 3-6 or 3-7 LED No POST diagnostic error on your Alienware or XPS PC?

Recovery Requires disconnecting All storage devices and using a USB 2.0 FAT32 flash Drive. Use a WIRED USB Keyboard.

must be usb2 media 16 gig 32 gig max MUST be FAT32

cannot be fat 16 or exfat or ntfs

SanDisk SDCZ60-016G-B35  Fat32 USB 2.0

Affected Systems:

Alienware R5/R6/R7/R8/R11
XPS 8910/8920/8930/8940

On a working machine
Download the BIOS update executeable
Erase the flash drive FAT32
Copy the file to the flash drive.
Hook up wired USB Keyboard
in an admin dos prompt go to the flash drive letter and
EDIT this is no longer needed to rename      BIOS_IMG.rcv

You can download the RCV file Directly now.

@Gosdra88 

See my post on bios recovery.

You are bricked but not yet Dead.  You need WIRED usb keyboard,  USB 2.0 flash drive FAT32  16 or 32 gigs.  32 gigs is preferrred because the recovery file is 12 gigs.

Most of the Details are in my prior post.

• Thank you for your reply ! 
• As far as i can see the file is only 12.19MB large ( not 12 gigs ) - am i missing something?
• I have dowoaded the file, i have copied it on my Sandisk 2.0 16gb fat32 usb stick using my laptop. After that, I inserted the USB into the 2.0 usb port on my aurora r7. When i pressed the power button, i have also maintained pressed the Ctrl-Esc keys. Even so, nothing appeared on the screen. The power button is still flashing 3,6 amber. Am i doing smth wrong? 

I don't know how to edit my previous reply, but I would like to mention the fact that I have also removed the ssd m2 and disconnected the hdd drive.

Re: It is possible that the MB is bricked? If it is, is there any chance to rewrite/flasg the Bios using a USB stick?

this is difficult for most users. you can in theory use a USB programmer to hard flash the cmos chip but in practice it is not so easy and takes experience.  if you can not revive the board then it is time to upgrade or ask how much Dell would charge you for a out of warranty repair of board, or buy a replacement board.  in 2021 for R7 I would suggest upgrade.  but the R7 case can not be upgraded to a non Dell mobo unfortunately (Dell made it hard for repurposing the case).

The main problem with Flash drives is that they are often faked.  Thats why you buy them retail.  8gig drives are actually less than 8 gigs total space because a gig is NOT 1000000 bytes its 1048576 bytes.  8 gig flash drives have 7 gigs space, 16 gig flash drives have 14 gigs space,  32 gig flash drives have 29 gigs space.   Cannot be smaller than 16 and cannot be larger than 32 gigs because otherwise its EXFAT not FAT32.  The series of blinks tells me the board is not dead yet.

The other route is to buy a working unit.

https://www.ebay.com/itm/114992766030