[Wolves] Ubuntu 14.04 Nvidia upgrade woes

[Andy Wootton]

My test upgrade to 14.04 on my Eee PC went without any serious issues, 
so I decided to press ahead with a Revo 3600 that I use regularly as my 
'quick web browse' box. BUT it has an Nvidia card. The last 2 Ubuntu 
updates have unhelpfully ignored my preference for Nvidia's proprietary 
binary drivers that 'just work' by installing the Nvidia drivers that 
"don't". I worked this out last time but this time something has gone 
horribly wrong. I tried to install the drivers from the command line but 
when I tried to reboot, I get only a desktop on which I can create 
folders or text files to my hearts content - but nothing else. I can 
only get a command line with <CTRL>/<ALT>/<F1> back to the console.

I seem to have a half-installed nvidia-331 that I can't remove. I get
"stop: Unknown instance:
userdel: existing lock file /etc/subuid.lock without a PID
userdel: cannot lock /etc/subuid: try again later." from aptget remove 
and I can't install because it already 'is'.

then it says the post-removal script returns error exit status 16, which 
I take to be due to the lock and dpkg returns 1.
I've tried every apt* fix or purge command I know but I don't know much.

Does anyone know an appropriate spell for such an occasion?

Cheers,
Woo