I fell into a snare when I downloaded and installed virtualbox 4.0 on my ubuntu 10.4. When I started virtualbox, I saw that the network icon on my desktop showed a red x showing I am disconnected. This happened shortly after I installed virtual box 4.0
I have searched through the web and found some people who have faced the same problem, but the solution didn't work of restarting, starting, and stopping the network manager. I was even thinking of uninstalling virtualbox but not the network connection.