[http://www.linuxquestions.org/questi... this happened
I definitely think its related to a symbolic link that NVIDIA makes to some xorg driver.
Well one possible cause then was that I had updated x11 following the latest slackware security alert.
seems we know the culprit.
if you upgrade can you try and find the changed link and post it? for future reference?
perhaps if we know the link that needs to be made reinstalling nvidia would not be required, but simply regenerating the link.
when it happened to me I forged ahead w/o writing it down. else I would tell you to try that.