Since the last update of my nvidia drivers on Ubuntu (15.04, 64 bit), I get a black screen when logged in Ubuntu.
A second monitor does not help.
Choosing the recovery mode on Grub doesn't help because:
Choosing different options on failesafeX does not change anything.
Choosing the dpkg option doesn't repair anything.
Going to the root shell prompt is useless: I can't use
apt-get install
orpurge
because the administration directory is locked.
I don't have a DVD of 15.04 and I don't want to reinstall everything. What are my options?