HELP Xserver cannot start

[Douglas Alves]

Hello Thomas

Ten days ago you suggested that I might be having trouble with an nvidia
driver. Another user suggested my HD might be full. I ran ds -k and it
shows 64% for my linux partition and 64% for my data partition (not /home).
I did run automatic updates from Synaptic so I don't know if there was a
security update.

How can I revert to a previous graphics driver from command line?