An old computer running Debian Testing is hanging randomly (have to reboot every time). I have reasons to suspect from the GPU or even the mobo.
Carsten Aulbert [ Editor ]
Usually if a system becomes stuck, you may get some information on the main text console screen, however, usually the space is too limited to get all the lines from a kernel panic (if it is a kernel panic).
If the system just stalls, your best bet is to start swapping components until the problem does not happen anymore – in this case it is actually a good thing if the system stalls quite often ;)