A reader of my-guides.net has send me the following guide which describes how to install AMD Catalyst Legacy Drivers in Ubuntu 12.10. These drivers are for AMD Radeon HD 2xxx-4xxx series card which are not supported by the latest proprietary AMD Catalyst driver version 12.9. I don't own an AMD card so I couldn't test. However from a search I did it works for most users.
Ubuntu 12.10 comes with xorg 1.13 while these drivers have support for older xorg 1.12. Therefore you have to downgrade your xorg. Tomasz Makarewicz has created a PPA that includes all the required packages you need to downgrade plus a fglrx-legacy package. Don't forget to uninstall any previous AMD proprietary driver before installing this one.
To install these packages, open a terminal and type:
sudo add-apt-repository ppa:makson96/fglrxsudo apt-get updatesudo apt-get upgradesudo apt-get install fglrx-legacy
You can generate xorg.conf file by the command:
sudo amdconfig --initial -f
If something goes wrong, you can revert everything by running the following commands:
sudo apt-get install ppa-purgesudo ppa-purge ppa:makson96/fglrx