I hate using the term shut down as this does not appear to be entirely true but for lack of a better term....
"Unlikely it is kernel. Much more likely is driver and|or setup."
This was a "plain vanilla" setup from Ubuntu-10.04-desktop-i386.iso from http://www.ubuntu.com/desktop/get-ubuntu/download
. There was no additional software added on my part although there was a large amount of updates that were installed on first start up. I have added Apache2.2 server (httpd), GIMP2 and pluggins since that time, but the mouse and shutdown problem occurred before this.
"Is this general to all DE, not just Gnome? =suggest try other DE and see."
Ubuntu uses gnome "out of the box"....Kubuntu uses KDE. From the net I have seen similar issues from several DE's so this may not be an issue to deal with just yet.
From what I can tell it seems as though the disappearing mouse issue seems to have been around since version 9.01 or since the H.A.L. was removed but I may be confusing things here.
"ANY key(e.g., ALT) should bring the monitor back if it has been blanked."
In the case of system shutting down, hibernating, or whatever it is doing, the Num lock light will turn on and off by pressing the key and pressing Ctl- Alt- Delete will cause the system to reboot so I assume the keyboard and CPU are still working but just pressing a key does not return the screen. The screen "appears" to flash with vertical bars showing from the top down to about 30 percent of the screen, as if the screen or the PC was trying to do a soft reset.
"The mouse should too but maybe not in your issue."
The mouse once "tricked" into working will stay on screen with out any further problem until the next time that the system is restarted and I assume it will occur when changing users (have not tried this yet, but will ...trying to reply here before reset happens).
"Sometimes even the CTRL-ALT-BKSPC will work to restart the X server."
I really wish it would but no luck there.
"You lose the DE and end up at login but no data should get corrupted."
Actually, I have had the reset happen in the middle of writing an email and the wise folks from Evolution appear to have a really good data save routine. One restore of the email and I was back in business, so kudo's to the Evolution team.
"Change the power management setup. Do not "blank" screen(xorg.conf) and do not use screensavers. If the screen blanks then, something is amiss."
In the order of sentences....Did it before coming here for help...never use them and don't blank....and finally yes it is.
I am not sure what is going on. I have been monitoring logs but I am not exactly sure where to look. Currently I have been keeping my nose in syslog and messages but I have only found one or two issues which seem to occur just before shut down and may be unrelated which is
rsyslogd: [origin software="rsyslogd" swVersion="4.2.0" x-pid="524" x-info="http://www.rsyslog.com"] exiting on signal 15.
and the other
pulseaudio: ratelimit.c: 6 events suppressed
there is also
kc4mts-desktop kernel: [ 3570.476022] [drm:i915_gem_idle] *ERROR* hardware wedged.
This comes up occasionally but does not appear to co-inside with the time of shut down, nor does it happen in all cases of shut down.
I will continue to look over the logs to see what is what.
"You system BIOS may have options for power management. Insure that they are correct."
I run 4 web sites off of this PC so I have power management pretty much off in the BIOS. I just changed the Systems settings for the monitor to never turn off (was set for 1 hour but did not seem to make a difference).