As of yesterday, my computer started turning itself off about 30s after I boot either Linux Mint or Windows 10 (both still in the loading mode, I never reach a usable OS).
I have removed the PCI card I had (only the GPU is installed at the moment), the second hard drive, the CD/DVD reader, it still crashes. I have even tried removing the main hard drive and booting from a bootable USB drive with Linux Mint on it, but the computer still turns itself off.
Memtest86+ can run for hours on end without the computer crashing and without detecting any errors. The CPU temperature stayed constant at about 70°C during this, so I don't think the crash comes from a CPU overheating problem.
I did not do any recent changes to the computer that would have created the issue.
I am a bit clueless as to what the problem could be and how I could fix it.