Where should I look for error messages after a freeze-up and reboot in Linux?

Question

I was forced to shutdown (using the power button) and reboot after my laptop froze with just a black screen.

After such an incident, where should I look for error messages etc. that might indicate what caused the freeze?

I am running Xubuntu (Lucid) with Fluxbox as my window manager. Any suggestions are welcome but I generally prefer to use the CLI.

Answer 1

If the screen and input devices (keyboard and mouse or trackpad) froze, the first place to start by looking would be in /var/log/Xorg.0.log (assuming that Xorg is running on the first display server).

If that doesn't yield any immediate clues, the next logs to check would be /var/log/messages.log and /var/log/dmesg.log.

If you are unable to find anything in the logs, and the freeze is happening with any frequency, you might be advised to check your memory with a utility like memtest86+.