What can I do when my system hangs completely?

[Rua]

A few times now, my system just suddenly froze and stopped doing anything at all. The mouse cursor wouldn't move, keyboard shortcuts did nothing (not even ctrl+alt+backspace), nothing would respond, the screen was frozen too. I ended up pressing the reset button because it's all I could do. I've yet to try out the REISUB SysRq code, but next time it happens I'll try.

Obviously this is a serious problem, but I don't really know how to find out what happened, because I didn't see a kernel panic or anything. Is there a way to find out what happened afterwards, maybe by reading log files? Where should I look?

[Habitual]

Are you able to inspect/clean the internals of the system?

I've had problems before with
1.) Dust Bunnies.
2.) loose connectors
and
3.) failing fans.

Edit:
If not a laptop...
re-seat all daughter boards and RAM sticks may also help.

Edit2:
Also

Code: Select all

dmesg

may yield some light.

[Rua]

It just happened again, and I tried ctrl+alt+sysrq+REISUB but nothing happened. The system is only a few months old so I don't think it broke so soon. It's also not overheating, it's only at 40 degrees.

EDIT: dmesg only seems to show messages from the current session, which doesn't really help at all. I just updated my kernel to 2.6.38-13, and just to make sure I tried out the sysrq code before it freezes, and it worked then.

[DrHu]

There are some areas you can look at, but consider that there may be bugs or other conflicts within the OS + applications (including desktop controls, such as Gnome/Kde/Compiz, Cinnanom etc etc..)
http://linuxgazette.net/101/tag/3.html

You might be able to generate a crash dump for later analysis, however such an exercise would entail detailed analysis, and is probably not something you would be much interested in

Debugging a Linux system..

[Rua]

It just happened again. It's getting quite worrying now... it happened maybe a few times in all those months since I first set up the computer and installed Mint, and now it happened three times in two days...

[monkeyboy]

Boot off a live release medium (not Debain based) and see if it locks or not. Good Luck