Ok several time now I have seen some strangeness with Ubuntu

I was in Mozilla reading a forum and the system just locked up witha blinking A., The one that indicates caps lock was just blinking and the mouse would not move. I had to power off the system.

Also I noticed that If I leave it for a while from time to time it is like there is a process taking up the cpu and wont release it. It takes for ever to do anything and the shutdown command takes for ever to come up. I endup powering off with the button.

Any ideas?

You could try using top in a console and see if you can pinpoint which app(s) is hogging your resourses.

The first one seems to be a system crash. You will have to check the system logs to see what exactly happened .In fedora I would have checked /var/log/messages. May be its the same for Ubuntu.

For the second issue, I guess you leave your firefox on when you are away (What made me guess this? Your first issue, the way you described it, the fact that u use Ubuntu... ). I have noticed that npviewer (a flash plugin) misbehaves a lot. You can try killing firefox and npviewer.bin to see if your system comes back to normal state.

When you see something is taking up lot of cpu, start a terminal program and run 'top'. Press, l. It will show you the process that use a lot of CPU. Press m, it will show you processes that use a lot of memory. Look for the 'PID' of the process that is taking all your resources. Issue the command 'kill -9 <PID of the process>'. (In Ubuntu, you will be logged in as a normal user. So the chances are less that you will kill any important system process.)

Btw, press 'q' to exit top.

All good ideas except that the machine would not respond to a any commands. I could not even launch a terminal to do top etc.

If it does it again Ill see what I can do. Ill keep a terminal up in the hopes i can access it if it hangs again and run top.

yes I left Mozilla up. I us it a lot so its always running

I had the same problem in debian.
It started when I bought a new belkin wireless router to support adsl2
Probably madwifi or the wpa or ....
The system locked up randomly
No problem when using another wireless router.

you can do
tail -f /var/log/syslog >> log.txt
to see the logs at the moment of the crash

here is my x11.conf file if that helps any.

root@cj454-lt:/etc/X11# cat xorg.conf
# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# Note that some configuration settings that could be done previously
# in this file, now are automatically configured by the server and settings
# here are ignored.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section "Device"
Identifier "Configured Video Device"
EndSection

Section "Monitor"
Identifier "Configured Monitor"
EndSection

Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
EndSection
root@cj454-lt:/etc/X11#

Is this your current xorg.conf file? There's nothing about your hardware in it. Do: lspci and post the contents to this thread.