I have VirtualBox 4.2 installed on Ubuntu Server 12.04, being managed with PHPVirtualBox. The server has fairly low-end specs, with only 512MB of RAM, and a Pentium 4 Prescott CPU @ 2.6 GHz (I read that people have virtualized on this exact computer).
When I go to install Ubuntu as a guest, it gets to about 13%-25% in the install process (actually copying things to the drive), and then I lose all connection to the server. I cannot connect with SSH, RDP (to the guest), or PHPVBox. When I go to login directly on the server, the login prompt is not working. I can actually erase everything on the display; including the "Username: " field. However, the hard drive is still very active. The only ways I can get back to the server are by waiting for the VM to abort (I guess) or by restarting the server.
Any advice on whats causing it? Let me know if you need any logs or extra info.