Possible Bad CPU?

[Outgoing]

I build my parents a nice new computer. I got it fully setup for them updated all drivers and fun stuff. I gave it to them and it ran great for about a month. Next thing I know pops calls and says he has a bsod. I go over and yup BSOD boot loop with different error each time.
Additional notes:
Before I wiped the computer it would boot into windows but as soon as I'd open anything I'd get a BSOD. If I booted into safe mode I was good. Browse around shut off services etc.

Troubleshooting:
- removed GPU
- tested ram with memtest over a whole 8 hour day. 1 stick each and both sticks. 0 errors.
At that point I figured bad windows. Went to reinstall after a nice HDD format and here's the fun. I get a BSOD upon trying to even load windows install. I did 7 pro, home 64 and 32 and win xp 32. Figured bad HDD so put in a SDD and same issue.
Called asus RMA'd the MB. They tested and "flashed" bios. I put it back in and problem persists.

Build
Asus TUF Z270 MARK 2
Evga before 1060 gtx
Corsair vengeance ram 16g
Sea gate barracuda HDD 2TB
Ocz SDD's
Intel core i5 3.5ghz

I'm at a loss here everyone I'm leaning to CPU and just dropping it off at a tech store as I don't have a spare CPU laying around. Any ideas? Thanks!

 

[lodders]

You have tested everything except the CPU and the PSU. Therefore one of them must be at fault.

 

[Outgoing]

Additional notes added.