LinuxQuestions.org - Computer completely locks up, seemingly at random

My computer sometimes stops working.

(1) First there is a loud clicking sound, close to the sound of a grandfather clock.

(2) Then the peripherals stop working; no number lock light.

(3) The harddrive light is usually lit up continuously at this time.

(4) Waiting patiently for half an hour does not resolve the situation.

(5) Have tried on distributions Debian and Ubuntu, with full official updates installed.

(6) I have checked /var/log/messages. Approaching the time of the lock-up I see:

Code:

Sep 17 12:28:27 zen gconfd (root-3179): SIGHUP received, reloading all databases

Sep 17 12:28:27 zen gconfd (root-3179): Resolved address "xml:readonly:/etc/gconf/gconf.xml.mandatory" to a read-only configuration source at position 0

Sep 17 12:28:27 zen gconfd (root-3179): Resolved address "xml:readwrite:/root/.gconf" to a writable configuration source at position 1

Sep 17 12:28:27 zen gconfd (root-3179): Resolved address "xml:readonly:/etc/gconf/gconf.xml.defaults" to a read-only configuration source at position 2

Sep 17 12:28:27 zen gconfd (root-3179): Resolved address "xml:readonly:/var/lib/gconf/debian.defaults" to a read-only configuration source at position 3

Sep 17 12:28:27 zen gconfd (root-3179): Resolved address "xml:readonly:/var/lib/gconf/defaults" to a read-only configuration source at position 4

Sep 17 12:28:27 zen gconfd (root-3179): GConf server is not in use, shutting down.

Sep 17 12:28:27 zen gconfd (root-3179): Exiting

Sep 17 12:28:50 zen gconfd (root-3472): starting (version 2.16.1), pid 3472 user 'root'

Sep 17 12:28:50 zen gconfd (root-3472): Resolved address "xml:readonly:/etc/gconf/gconf.xml.mandatory" to a read-only configuration source at position 0

Sep 17 12:28:50 zen gconfd (root-3472): Resolved address "xml:readwrite:/root/.gconf" to a writable configuration source at position 1

Sep 17 12:28:50 zen gconfd (root-3472): Resolved address "xml:readonly:/etc/gconf/gconf.xml.defaults" to a read-only configuration source at position 2

Sep 17 12:28:50 zen gconfd (root-3472): Resolved address "xml:readonly:/var/lib/gconf/debian.defaults" to a read-only configuration source at position 3

Sep 17 12:28:50 zen gconfd (root-3472): Resolved address "xml:readonly:/var/lib/gconf/defaults" to a read-only configuration source at position 4

Sep 17 12:40:23 zen gconfd (root-3472): SIGHUP received, reloading all databases

Sep 17 12:40:24 zen gconfd (root-3472): Resolved address "xml:readonly:/etc/gconf/gconf.xml.mandatory" to a read-only configuration source at position 0

Sep 17 12:40:24 zen gconfd (root-3472): Resolved address "xml:readwrite:/root/.gconf" to a writable configuration source at position 1

Sep 17 12:40:24 zen gconfd (root-3472): Resolved address "xml:readonly:/etc/gconf/gconf.xml.defaults" to a read-only configuration source at position 2

Sep 17 12:40:24 zen gconfd (root-3472): Resolved address "xml:readonly:/var/lib/gconf/debian.defaults" to a read-only configuration source at position 3

Sep 17 12:40:24 zen gconfd (root-3472): Resolved address "xml:readonly:/var/lib/gconf/defaults" to a read-only configuration source at position 4

I am uncertain if these messages are connected to the lock-up problem. Where do I begin to diagnose this problem?

Assistance much appreciated.