I have an Ubuntu 12.04 workstation at home which I also use when I'm at work. My girlfriend also uses it when I'm at work. The arrangement is that I connect through ssh while she is physically working at the machine.

I would like to be able to have a remote desktop session on my user without having her log off. So far, I have been able to remotely connect to my workstation using x11vnc and ssh with the following command

sudo x11vnc -create -safer -localhost -nopw -once -auth /var/run/lightdm/root/:0 -display :21

I'm using Windows as the client computer with putty and tightvnc.

I've read that I have to start a X server on a specific display before running the x11vnc command. However, every time I do it, I log my girlfriend out of the machine and force the physical display to show what I am doing.

Is there a way to remotely connect to my workstation and have an X session without logging anybody out?

I've tried normal X11 forwarding through putty/xming, but it is painfully slow

Thanks!

EDIT: In case people have problems with this in the future, I used the guide in the following website:
http://rbgeek.wordpress.com/2012/06/25/how-to-install-vnc-server-on-ubuntu-server-12-04/
I just tested it, and it works great: good speed, vnc over ssh, and nobody gets logged out