Re: GUI not working after upgrading to 12.10
You said you have a Radeon video card, and from what I could find, that uses an Xpress chipset.
That's a very old chipset for which AMD restricted drivers haven't worked in a long time -- so if you were using the default Radeon open-source drivers in 12.04, you should not have suddenly encountered a video driver problem upgrading to 12.10.
So, while it's possible, I suspect that the problem is not the Radeon video drivers.
Ubuntu 16.04 Mate, Mint 18 Mate; MS Win 8.1, MS Win10 Pro.
Will not respond to PM requests for support -- use the forums.