got this bug when i tried to install Ubuntu 12.10 over my 12.04 LTS stable install last night on my HP AMD 64bit laptop
Had a blank desktop, as you describe. managed to fix it by doing this;
sudo apt-get remove fglrx
sudo reboot
Now its all back to normal again (although i may not have optimal gfx drivers)
got this bug when i tried to install Ubuntu 12.10 over my 12.04 LTS stable install last night on my HP AMD 64bit laptop
Had a blank desktop, as you describe. managed to fix it by doing this;
sudo apt-get remove fglrx
sudo reboot
Now its all back to normal again (although i may not have optimal gfx drivers)
:) Simon