X399 Taichi + 1900x boot loop

Hey guys, I'm having my newly assembled PC rebooting in a loop with Dr. Debug showing '00' code. This happened after I updated BIOS to 5.10 version. Before that I booted the PC and saw different codes being displayed by Dr Debug successively but after a while they disappeared so I thought that everything ran smoothly. I'm a beginner so I don't know if there's a BIOS preinstalled on a motherboard. Anyway at that point my display did't show anything so I decided to update to the latest BIOS version through Flash button. I used the manual and everything went as described there. However, when I booted system after updating I got '00' code and currently can't do anything about it. I tried to clear CMOS values using button but it didn't help. My power connection also should be fine (it's one 24 pin, one 8pin and one 4pin cables connected to motherboard). I also tried to switch to different BIOS (I thought maybe the new one is a problem since initially everything seemingly worked) but got the same boot loop. Current BIOS version installed is 3.20. So now I'm a bit lost with my first built so please give your thought. 

Also, while in the reboot loop power switch button stops working in a normal way. That is I can switch the PC off only if I hold it for some time. Just pressing it one time doesn't do anything.