Hey there,
So I have a problem after installing manjaro: When i wanna go to the BIOS by pressing the DELETE button, it shows up the BIOS but then freezes randomly. And here’s the weird thing: If I press F11 (to open bootable devices) and then click on “goto setup” it basically opens the BIOS without any errors.
Btw, I am using a mainboard named “MSI x470 gaming pro”.
It would be very nice if anyone could help me out 
Welcome to the forum! 
Since you’re a new user on this forum, I’d recommend you check this out:
Please boot from a Manjaro live environment and provide further information as per above.
From what you described in your OP, it sounds like your BIOS/UEFI is corrupted. There is a chance that you installed Manjaro over the BIOS already corrupted and then the issue became evident after installing Manjaro. This might be the result of abrupt power-offs, among other hardware misuse. In that case, best course of action is to follow the BIOS recovery procedures from your hardware manufacturer.
Also, I would like to give you an introduction to the forum rules. Please note that this thread may be closed if deemed off-topic as per rules.
Non of ordinary USB burning software are patches or changes the BIOS/UEFI settings.
AFAIK Manjaro itself also do not do that at least by default.
So it is your hardware or UEFI problem. What could it be?
-)
-) USB stick’s or USB port connectors are dirty, at least plug and unplig a USB device to the same port a few times before to leave USB device in port and try again after PC reboot.
-) USB port is somehow corrupted or UEFI does not supports boot media from some group of ports, please try another port on the back panel of a PC.
-) UEFI tries to scan all files on a USB device for somewhat or had recognized some file on that USB stick as it’s system file (for example as part of firmware)
-) USB stick is broken - try other
-) try another way to load image: try ventoy package and after it’s created a boot media with ventoy's system files, upload the image file (*.iso) to that new user partition labeled Ventoy by default. Try to load fromm USB stick.
-) PC’s UEFI on USB 2.0 port may not recognize USB 3.0+ sticks as boot media. Try USB 3+ ports or try USB 2.0 stick in USB 2.0+ port.
At the moment I do not know what else.
Do you have latest UEFI fimware? Check your PC or motherboard manufacture’s website to find the latest version and read instruction how to update UEFI firmware at least twice.
As @El_Brujo and @alven pointed out - not being able to go past the bios/uefi screen means:
- Crappy usb stick - try another one (once i had a usb stick that fried 2 of the available ports. because it was a little bent)
- Some stupid bios/uefi toggle about usb booting/usb power/hdd spindown/hdd wake timer… etc
- Broken bios/uefi config - Make a backup of the current bios/uefi config on a fat32 hdd or usb stick, reset to optimal bios defaults and try to boot directly from the hdd/ssd/nvme via the mainboard boot menu.
The BIOS/UEFI itself is VERY unlikely to be faulty, unless as a result of a firmware flash gone wrong!
Edit: I just remembered another idiotic scenario - if you do not need the built-in LAN card (if you have one) - disable it and try again. Sometimes power outages/lightning/crappy PSU - can hurt the networking hardware and prevent the bios/uefi from completing a self-check.
@neckfreak Your answer helped me very much. It came out that I had to enable Network stack on my LAN card (I couldnt disable it because I am using a cable). Idk why, but now it works 
OP asking for hardware support.