Since I don't know exactly what and where to find to eventualy solve my problem, I post it here.
At some point, while working under user login on my laptop running mandrake 9, my keyboard stopped working. Stroking any key (except the Fn key -- Dell Laptop, and Ctrl-Alt-Back) has no effect anymore. I cannot even enter the root passwd to check things...

First I thought it was because my / partition was low on memory. Then I looged as root, and did free some space there. No way.
I found out that from root I was able to connect as user, and then using the keyboard as usual.

When I go back to the user session (I use gnome), still no keyboard.

The problem is that I don't know what to do and what to check... Any hint or help would appreciated!!

Thanks by advance.

If I login with KDE, there is no problem. It might be a gnome-related problem...

Well, after a few hours trying to figure out whats going on, now it works... Some kind of Holy Spirit operation in my back. Sorry for bothering...