10.04 crashes

[dbclinton]

Hi,
I'm experiencing serious crashes (three or four a day) on my new
edubuntu 10.04 install. This is the third fresh install I've done - on
two separate hard drives - and the problem persists. With no clear
trigger, the screen will go blank, followed by strange black and white
patterns and then the monitor will lose its signal. These will cycle
through indefinitely. Interestingly, while my computer (a thin client
server) is affected, the thin clients themselves can continue working
for half and hour after the crash.
Here is the relevant log output:
==============
auth.log:
May 12 18:48:56 rishon polkitd(authority=local): Unregistered
Authentication Agent for session /org/freedesktop/ConsoleKit/Session2
(system bus name :1.33, object
path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_US.utf8)
(disconnected from bus)
May 12 18:48:56 rishon gnome-keyring-daemon[1312]: dbus failure
unregistering from session: Connection is closed

syslog:
May 12 18:39:06 rishon AptDaemon: INFO: Initializing daemon
May 12 18:44:07 rishon AptDaemon: INFO: Quiting due to inactivity
May 12 18:44:07 rishon AptDaemon: INFO: Shutdown was requested
May 12 18:48:53 rishon kernel: [11934.376061]
[drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
May 12 18:48:53 rishon kernel: [11934.376080] render error detected,
EIR: 0x00000000
May 12 18:48:53 rishon kernel: [11934.376178] [drm:i915_do_wait_request]
*ERROR* i915_do_wait_request returns -5 (awaiting 979106 at 979105)
May 12 18:48:55 rishon kernel: [11936.292165] [drm:i915_gem_idle]
*ERROR* hardware wedged
May 12 18:49:00 rishon gdm-simple-slave[6803]: WARNING: Unable to load
file '/etc/gdm/custom.conf': No such file or directory
May 12 18:49:01 rishon kernel: [11941.894959] __ratelimit: 15 callbacks
suppressed
May 12 18:49:01 rishon kernel: [11941.894981] ica[1567]: segfault at 0
ip 00524405 sp b74a8b70 error 4 in libQtCore.so.4.6.2[496000+276000]
May 12 18:49:01 rishon pulseaudio[6814]: pid.c: Stale PID file,
overwriting.
May 12 18:49:02 rishon acpid: client 6021[0:0] has disconnected
May 12 18:49:02 rishon acpid: client 827[0:0] has disconnected
May 12 18:49:02 rishon acpid: client connected from 6821[0:0]
May 12 18:49:02 rishon acpid: 1 client rule loaded
May 12 18:49:02 rishon pulseaudio[6814]: main.c: Unable to contact
D-Bus: org.freedesktop.DBus.Error.NoServer: Failed to connect to
socket /tmp/dbus-KtiXQ9KyA7: Connection refused
May 12 18:49:03 rishon bonobo-activation-server (dbclinton-6830): could
not associate with desktop session: Failed to connect to
socket /tmp/dbus-KtiXQ9KyA7: Connection refused
May 12 18:49:03 rishon pulseaudio[6828]: pid.c: Daemon already running.
May 12 18:49:04 rishon pulseaudio[6837]: pid.c: Daemon already running.
May 12 18:49:04 rishon kernel: [11945.170708]
[drm:i915_gem_entervt_ioctl] *ERROR* Reenabling wedged hardware, good
luck
May 12 18:49:04 rishon kernel: [11945.552023]
[drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
May 12 18:49:04 rishon kernel: [11945.552036] render error detected,
EIR: 0x00000000
May 12 18:49:04 rishon kernel: [11945.552106] [drm:i915_do_wait_request]
*ERROR* i915_do_wait_request returns -5 (awaiting 979121 at 979105)
May 12 18:49:06 rishon kernel: [11947.660091] [drm:i915_gem_idle]
*ERROR* hardware wedged

kern.log
May 12 18:48:53 rishon kernel: [11934.376061]
[drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
May 12 18:48:53 rishon kernel: [11934.376080] render error detected,
EIR: 0x00000000
May 12 18:48:53 rishon kernel: [11934.376178] [drm:i915_do_wait_request]
*ERROR* i915_do_wait_request returns -5 (awaiting 979106 at 979105)
May 12 18:48:55 rishon kernel: [11936.292165] [drm:i915_gem_idle]
*ERROR* hardware wedged
May 12 18:49:01 rishon kernel: [11941.894959] __ratelimit: 15 callbacks
suppresMay 12 18:49:56 rishon kernel: imklog 4.2.0, log source
= /proc/kmsg started.

=====================
I appreciate your help!
David