sudo apt-get install vnc4server
But VNC viewer at a Windows computer could not access the Ubuntu.
Then, I did:
sudo apt-get install gnome-core
But still no access.
Ubuntu already has a VNC server called
If you run
you will get a dialog box to help you configure the VNC server, and even make your computer accessible for VNC from the Internet (if you wish to).
I recommend removing the packages you installed and use vino.
In addition, the pre-installed VNC client for Ubuntu is