I had screwed up my system(Ubuntu box) by multiple installation of the ATI drivers. I installed the proprierty ATI drivers from the driver file downloaded from their site named ati-driver-installer-9-3-x86.x86_64.run. Then I reinstalled it again by Envy and also by the Hardware drivers section. Result - no display on login. Not even booting into recovery console and fixing X-server worked. The bottomline is never screw with your video drivers. I had to manually remove the fglrx drivers to get back display. 1. Booted into recovery console and fell into root shell. 2. apt-get remove xorg-driver-fglrx 3. But I read in some forum that "....where proprietary drivers are concerned is that Ubuntu/Debian has a conflict resolution system to redirect certain libraries that conflict called dpkg-divert, since binary drivers like ATI and Nvidia especially have a bad habit or creating incompatible libGL.so binaries that blow the system away if they aren't accomodated and removed properly l...