Question PC keeps crashing

[Mivraw]

Hello everyone!

I have had my PC for about 1 and a half year now. Its been working fine i had some minor issues before my Mainbord was broken and my PC kept crashing when under heavier loads. Then my CPU was broken and it also kept crashing under heavy loads. But my Mainboard and CPU got replaced and it has been working perfectly fine for more then 1year since. But for a couple of weeks now everytime i start my PC and (for example) i get to the home screen i start downloading a windows update it gets to 5% Then my PC freezes completley i cant do anything i have to restart and when i then restart and start downloading the update again same happens over and over. This also happens with downloading other things such as games / graphics cards updates and so on. I barely have 30seconds on my home screen before it crashes/freezes because a automatic update of some program starts. Its really frustrating since its the 3rd time my PC is broken in less then 2 years and i cant figure out why. My thought currently would be the ssd being broken its a Samsung 970 evo m.2 with 250gb. Its the only drive i use in my pc currently since i already removed the other 2 hdds because i thought its one of them being broken. Other PC parts are
Intel core i9 9900k (not overclocked) (new replaced)
Gigabyte RTX 2080 Windforce OC 8gb
16gb DDR4 trident z g.skill (3200) Ram
Gigabyte Z390 Aorus Ultra Mainboard (new replaced)
750 watt be quiet dark power pro 11 (80+ platinum)
Corsair hydro h150i water cooling
Be quiet dark base pro 900 tower.
I had no heat problems or Ram issues in the last tests i did before my pc kept crashing.

 

[helpstar]

check windows integrity
open the command prompt as administrator and type DISM /Online /Cleanup-Image /RestoreHealth
https://www.lifewire.com/how-to-open-an-elevated-command-prompt-2618088
https://answers.microsoft.com/en-us...em-files/bc609315-da1f-4775-812c-695b60477a93


clean boot
https://support.microsoft.com/en-us/help/929135/how-to-perform-a-clean-boot-in-windows


check the memory by running memtest.org usb autoinstaller (bootable USB flash drive)


check the hard drive for errors with its manufacturer´s tool

 

[Mivraw]

Okay so first of all thank you for the quick answer eventho it took me some time to reply. I tryed some of the things you wrote down everything worked fine i somehow was able to fully update windows and all my drivers and so on. Untill i realised that usually my PC wouldve already crashed after 30seconds. But i managed to updated and install everything i needed. Basiclly i somehow realised i was connected to the internet the whole time without a LAN cable which usually i would always use. So i plugged it in and let me tell you i didnt take more then 30secs for my PC to crash like before. So i restarted it and same happend again instantly crashed when i tryed to download something. I unplugged the LAN cable again and went back to WLAN. Well nothing no crashes nothing. I downloaded a couple a games other stuff even played a few games no issues. Plugged the cable back in instantly crashed. Since i am useing the same cable with my old pc and everything is working fine. I would guess the Network port from my Mainboard is broken. If you agree with this. Do i have to buy a new Mainboard or can i get a replacment for the Network port plus is it bad that the network port is broken (can it damage other parts of the mainboard.) Or would it be totally fine for me to continue useing my PC just with WLAN instead