When running cudaminer once it tries to initialize the card the entire screen freezes. The computer itself is still running but the Xorg is done for, you cannot even switch to another console window and must reboot (even an mdm or Xorg restart does not help).
At first cudaminer will give you these errors:
...retry after 15 seconds
GPU #0: Geforce 210 with compute ca........
The solution was to reinstall the vbox dkms package and do a manual modprobe of the modules it makes.
I never sorted out the unable to start due to the USB issue, I did have the guest additions installed but the only way to boot was to change the pointing device from USB to PS2 and then to disable the USB controller (if your pointing device is set as USB, disabling USB will not work because it will re-enable by default when it sees your pointing device is USB, this is w........