New PC - Internet timing out & booting issues.

[WK1989]

First and foremost i would like to apologize for my awful grammer and any potential typo's english is not my first language.

Ok so a week and a half i built my very first PC.
 

specs

Z390 Aorus Elite
i5 9600k
G.Skill Ripjaws 16GB DDR4 3200MHz (F4-3200C16D-16GVKB)
GTX 1060 6GB (from old pc)
3 SSD's (from old pc)
1 HDD (from old pc)
Corsair RM650x
 

From day one it was kind of an headache PC i installed Win10 and updated to version 1803 which seemed to take 4/5 hours to fully download and install on a 200mbps connection.
After it was set up and installed i lost all internet connection out of nowhere.

Cue another Win10 install this time to version 1809, everything seemed fine and dandy at first but every so often my internet connection would time out shortly. I would stay connected to stuff like teamspeak and in games but get thrown off discord and struggle to load any site for a short while.
 

After some googling and consulting with my friends we tried stuff like reinstalling the internet drivers, changing DNS to google's DNS etc. Running some command lines in a specific order
 

winsock reset
netsh int ip reset
ipconfig/release
ipconfig/renew
ipconfig/flsuhdns
 

To me it felt like it improved somewhat i would still have the occasional time out but not as often as it did before which made me hope it would be software related and not be a faulty ethernet port or something on the motherboard.
As i woke up today i already wanted to post the issue here in the hopes of someone with more knowledge then me being able to help me.
That was until i hit the power switch on my PC and it did absolutely nothing. There was absolutely no response from my PC no start up, no case fans, no beeps just silence. 

I flicked the switch on my PSU off and back on again hoping to see the little flicker on my motherboard which i knew it did but there was nothing i did notice the ethernet port flickering. 
Standing infront of the PC messaging my gf saying my PC had turned into a brick it just booted itself out of nowhere, since i had the monitor already on i saw it booted to the Aorus logo and then crashed and instantly booted itself again and now it seems to be working as i am typing this post on the PC right now, Though i am scared what will happen if i do shut it down now.

So can anyone please help a first time builder in need? is my motherboard dead or faulty? what is the best course of action for me to undertake?
 

---Further Info---
 

After i had written this text i saved it on a USB stick incase the pc would shut down, as i was about to post this my PC did in fact shut down but my motherboards lighting stayed on for some reason. the pc turned into a brick again. after some time i pulled the usb stick out of the pc at which point it booted itself again.

[Turretgaming]

do you have the drivers for the cpu, gpu, wifi chip, nic/ network card, and any-other thing because that could cause this issue

[WK1989]

I have the latest nvidia drivers installed and took the network drivers of my motherboards manufacturer website 

[Sylvie]

It could be a power issue. Do you have a spare psu to test?