Unfixable Randomly Rebooting Computer

[mcdarkveil]

My custom built desktop has been broken for almost a year now, and throughout this year I've been getting RMA replacements in an attempt to fix it. It is at the point where it is almost a brand new computer, and I have no clue what to do next. It worked fine for around 9 months before I started having any problems. I brought it into a local repair shop and they haven't been able to help me with it either.

The reboot seems to be hardware related, as the computer completely turns off before coming back on. All of the lights go off and it turns off instantly, with no information given.

Every time I completely refresh the computer, it takes a while before the rebooting starts happening again, but once it does, it gets stuck rebooting so frequently, it's hard to keep it on long enough to check anything software related. It will get stuck in rebooting cycles where it can't fully start up.

Here is a list of the components in this computer:
CPU: Intel Core i5-6500
Motherboard: MSI Z170-A PRO
Memory: G.Skill Trident Z 16GB (2 x 8GB) DDR4-3200
Hard Drive: Seagate ST1000DX001 1TB 3.5" 7200RPM Hybrid
Video Card: EVGA GeForce GTX 970 4GB SSC ACX 2.0+
Case: Rosewill CHALLENGER ATX Mid
Power Supply: EVGA SuperNOVA P2 650W
Optical Drive: LG - WH16NS40
Operating System: Windows 10 64-bit

I have RMA replaced the CPU, Motherboard, Memory, Video Card, and Power Supply, and I've temporarily removed every non-vital component to check if it would still reboot, and it did. I have removed the Hard Drive and put in an SSD temporarily as well, and both drives have been completely wiped and had fresh Windows installations many times. The wires were not replaced with the power supply RMA, so all of the wires are still the same. I have moved houses since the issue started occurring, so I can most likely say it is not an issue with the power outlet. No other computers plugged into the same outlets have had any issues.

 

[Lutfij]

You may want to see if a recreation of your USB installer for Windows 10 and reinstalling your OS solves the issue? You might also want to make sure your motherboard BIOS is up to date. Speaking of BIOS, can you maintain any length of operation while only in BIOS? If so then you can see if it reboots there after a period of time. If it does reboot then the issue can and will be compounded to the PSU.

 

[mcdarkveil]

You may want to see if a recreation of your USB installer for Windows 10 and reinstalling your OS solves the issue? You might also want to make sure your motherboard BIOS is up to date. Speaking of BIOS, can you maintain any length of operation while only in BIOS? If so then you can see if it reboots there after a period of time. If it does reboot then the issue can and will be compounded to the PSU.

I have updated the BIOS and all of the drivers. The computer does not seem to reboot while in only the BIOS, although it is hard to tell because getting the rebooting to start can be very very random. I'm going to now attempt to install Windows 7 Ultimate instead of reinstalling Windows 10, since I've already reinstall Windows 10 many times, and even gotten a completely different key and used that after formatting the drive.

 

[mcdarkveil]

You may want to see if a recreation of your USB installer for Windows 10 and reinstalling your OS solves the issue? You might also want to make sure your motherboard BIOS is up to date. Speaking of BIOS, can you maintain any length of operation while only in BIOS? If so then you can see if it reboots there after a period of time. If it does reboot then the issue can and will be compounded to the PSU.

I can now confirm it is still randomly rebooting with Windows 7 Ultimate. It also can reboot too quickly to even load the BIOS, so I really don't think it's to do with Windows. I also just now did a BIOS update, but no good. So you say it must be the PSU?