I believe that Ubuntu uses XF86Config-4 instead of the newer xorg.conf file, but if you have xorg.conf copy those. Also some produce XF86Config and if you have BOTH XF86Config and XF86Config-4, the -4 one gets used... if not then the when without the suffix gets used. (this was done for backward compatablity from years ago)
to backup:
sudo su -
(to become root)
cd ~/
cp /etc/X11/XF86Config-4 ./XF96Config.backup
That's it.
With your 815-based video card.. It's very slow. I have a similar, newer Intel card in a old laptop (which I sold a while ago).. I think it's a speed problem.
I looked in google and found this thing related, and it's in the Ubuntu forums (google'd version of the forums is low-fi, to get to the nicer version you go to
www.ubuntuforums.org)
http://ubuntuforums.org/archive/index.php/t-4124.html
The guy had bars, and snow and some weird effects with his mouse cursor. To fix it he had to change the color depth to 16 bit, from the default 24bit (same as 32bit in windows).
Section "Screen"
Identifier "Default Screen"
Device "Intel Corporation 82815 CGC [Chipset Graphics Controller]"
Monitor "FLATRON 775F"
DefaultDepth 16
SubSection "Display"
Depth 1
See the 'DefaultDepth'? Make sure that is 16 there and not 24.
Backup your file before editing it, of course. Always do that. So that if you make a mistake (we all do) you won't loose your original settings.
If you can only use command line and are unfamilar with unix style text editors, give 'nano' a try. Uses ctrl-button combos for all the commands... like ^x and such.. (were ^ is the shorthand for ctrl)
Hope that helps.