Re: Virtual box
How did you install virtualbox? Did you download the deb file from https://www.virtualbox.org/wiki/Linux_Downloads or follow instructions farther down the page for "Debian-based Linux distributions"?
I did the latter (adding the repository and using sudo apt-get), and the only thing I had to do after installing it was add myself to the vboxusers group (although, I am running 64-bit 12.04). I also added the "Extension Pack" from https://www.virtualbox.org/wiki/Downloads
VboxGuestAdditions.iso ends up in /usr/share/virtualbox which you can mount on the virtual CD of a guest operating system. Although, in certain Linux distributions you might need to uninstall their older default guest additions before installing this matching version.
i5 650 3.2 GHz, 8 GB, nvidia GTX 550 Ti @ 1080p (year old GT 430 began freezing) and assorted other computers