I started to use Linux around 10 years ago (Red Hat, Slackware and Mandrake)
then used only Windows XP during the last 3 years. Having replaced my lap-top 2
weeks ago I double boot it with XP and Ubuntu Karma.
All ran perfectly until yesterday when I probably made a big mistake : while
removing a program as "sudo" with the Ubuntu logitheque (this program being
Python-6), to enjoy my time as it was uninstalling I opened an other desktop to
run "earth-3d" which had been freshly installed.
Suddenly the graphic display collapsed and was replaced by the command line. I
tried to reboot and got the message :
"AIGLX error : dlopen of /usr/lib/dri/sis671_dri.so failed
(/usr/lib/dri/sis_dri.so : cannot open shared object file : no such file or
directory"
None of the recovery procedures proposed worked and there seemed to be no
executable file like "reconfigure"...

This was my first serious crash with Linux in years. I may be wrong but I
consider that when I run a program as "sudo" I must run only one program at a
given time, wait until it is finished to do something else and see Linux as a
multitask system only when run by an "ordinary user".