The boot drive is a new SSD, but there is one older hdd storage drive. the OS used to be installed on an older ssd, but my friend first thought it was an issue with his drive and just upgraded and reinstalled the OS (Windows 7! - i urged him to upgrade)
so we did a bios update (still pretty old, but it was an update), and we did check the ram with memtest86. The memory seems to work fine. but the problem is still there.
when i first saw the system i tried to replicate the issue by turning off the power switch on the PSU and wait for a couple of minutes. i do not think it was 8 minutes though... so i will give that a try.