Question Constant BSOD after fresh Windows 10 install ?

Feb 14, 2022
Hi all, hoping to get some help with an issue my brother's PC is happening. Unfortunately I am not overly savvy with software problem solving, no issue building/moving parts, but once a PC is up and running I am not so helpful. So if any explaining could be done with an idiot in mind, that would be appreciated!
i5 2500k
970 GTX
8gb Corsair XMS RAM (4x2gb)
AntecTruepower 650W
Asus P8P67 Pro (rev.1.01 according to board)

USB Win 10 Installer media (which is known to work as I created it and used it on two PC's within the last week)

So, his PC currently runs in Win 7 and has no issues at all. Decided to upgrade to Win 10 using a different HDD. I removed his HDD(Win7) and added an old but empty HDD and installed Win 10. Started to install tings - Chrome,Skype, Steam, Nvidia Drivers. At any point during this it would crash. Tried a few times, crashes happen randomly but frequently. Decided maybe the HDD was faulty (it is old). Tried with another old HDD, same issue (also crashed once during set up)
Installed brand new 120gb SSD. Installed win 10, crashed during Cortana set up process, restarted and completed set up. Same issue as the HDD. Crashes constant, cannot even get far enough in a Steam verification process to play a game before crash.

Swapped out GPU with another 970 since I had it on hand and figured I would rule it out. Same issue of crashes.

Was going to do memtest, but since PC crashes so frequently that seemed pointless as I would be lucky to get as far as starting it before a crash will happen. But I did notice something odd -in Win 10, the System was stating 4gb RAM not 8gb. I took out the RAM and used 2 sticks instead of 4 and the 4gb still showed up (only now it is correct). Still crashed. I swapped around the sticks, still crashed. Swapped around slots used, no change. Tried two spare sticks, crashes continued.

I am at a loss on what to do. I am guessing, since everything works in Win 7, it is likely a Software problem rather than hardware (but went through all the above any way since it is the stuff I am most comfortable with) though the mystery of RAM only being recognised as 4gb does confuse me.

I see mention of Bios updates when doing some google searching, the P8P67 Pro is old and never been updated, but I am not overly comfortable doing it due to risk of total failure, and trying to be sure which board version I have and therefore the correct install I would need. If it must be done, any help on how to confirm board/correct software would be appreciated.

Otherwise, I guess one of the many drivers installed in Win 10 is the problem? Since it works in Win 7 it is the only thing I can think of.

Thanks for any help