I had to downgrade Xorg from 1.13 to 1.12 in order to use the fglrx-legacy but it (fglrx-legacy) didn't work for me neither fglrx. So, is it possible to upgrade Xorg back to 1.13? and how?
Install Synaptic package manager, find xorg-server package with ppa version 1.12, then from menu choose 'force version', and select 'ubuntu-updates'. After all, you'll loose all the system, but that's repairable: in terminal, type
Have fun! :-)