Computer does not reset

I have a BRIX gb-brr7h-4800 minicomputer. When I reset the computer from the reset panel, the system shuts down but does not reset. The screen turns black, power stays on, but no reset happens. I have to long-press the power button, then turn on again to get a fresh boot.

The same happens when I ctrl-alt-del from the boot menu. So probably this is rather a BIOS setting. However, the bios is very limited with only a few settings and I could not see anything relevant. Also this computer got repaired as the graphics card died. Before, there were no problems with the reset procedure but probably the mainboard was swapped.

Well, it may be because of a hardware fault. On the other hand, you can also check for power supply because if the PSU (Power Supply Unit) does not supply power, then it can cause unexpected behavior. You can try both thing and can fix this error.
Thanks

Thanks. The computer has an external power supply (NUC form factor). I have no indication that the PSU has problems (single, 19V rail) as the computer is otherwise completely stable. I would also suspect a hardware problem as I have never heard of such reset problems before and the fact that the previous unit did not experience the problem.