Sounds like you probably have a proprietary driver compiled against kernel version X, but have upgraded to kernel version Y. Because they are closed source, the driver has to be rebuilt for a given kernel version, which means you have to take care to match your kernel and video driver versions, else it'll break.
** Changed in: xorg (Ubuntu) Status: New => Won't Fix -- upgrade breaks graphic drivers and x, preventing login or startx https://bugs.launchpad.net/bugs/464591 You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in ubuntu. _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp