pointer stuck at upper left corner

[Pierre Frenkiel <pierre.frenkiel@gmail.com>]

After a power failure, I have a seriuous problem with my mouse:
It stays at the upper left corner of the screen, and when I move the mouse,
the pointer just moves a few mm, and returns to the corner.
This happens only in graphic mode, even at the login screen.
In all the consoles, the mouse works perfectly, and also if I boot
from a live cd. So, it's not a hardware problem. I thought it was related
to the X server, so I first re-ran the config program
            sudo dpkg-reconfigure -phigh xserver-xorg
which didn't solve the problem.
Then I re-installed all xserver packages ==> problem remains.
Now, I've no idea where to look at.
I would appreciate any help, as working only in console mode
is a strong limitation !
,
--
Pierre Frenkiel