my ubuntu 12.04 freezes on start up after I changed graphic card. Previously I had Ati Radeon saphhier 6850 and everything was ok, then I removed it and put some old nvidia graphic, and even then it was ok, and now I got new one, Ati Radeon Saphhire 7850... Ubuntu loads untill welcome screen then it freezes, mouse is working but interface is unclickable, and lower right corner says amd hardware unsupported. I need to do hard reset. Any help?
You must install the proper driver for your video card. In order to do that go to AMD website and download the proper file, then reboot your system and choose