[SOLVED] Upgrade to 13.04 broke Virtualbox 4.1

The upgrade to 13.04 broke my virtual box installation on my laptop. To correct the problem I did the following:
1. From Ubuntu Software Center I uninstalled Virtualbox 4.1.
2. I downloaded the current (4.2) Virtualbox from www.virtualbox.org.
3. Double-clicked on the downloaded deb file.
4. Installed Virtualbox 4.2 from inside Ubuntu Software Center.
5. Started Virtual Box. All pre-existing VBOX devices were present.