0.sudo apt-get purge fglrx-modaliases fglrx-amdcccle fglrx-kernel-source xorg-driver-fglrx xorg-driver-fglrx-dev
1.reboot
2.sudo rm -r /etc/ati
3.sudo rm /etc/X11/xorg.conf*
4.Install fglrx from synaptic or sudo apt-get install fglrx
5.sudo aticonfig --initial
6.Reboot

Work flow
One line : sudo apt-get purge fglrx-modaliases fglrx-amdcccle fglrx-kernel-source xorg-driver-fglrx xorg-driver-fglrx-dev ; rebbot

After reboot : sudo rm -r /etc/ati ; sudo rm /etc/X11/xorg.conf*; sudo apt-get install fglrx ; sudo aticonfig --initial ; reboot

Again after reboot: Enable desktop effects from appearance.

Details:
Step 0 => Removal of the old drivers.
Step 1 => Rebooting, this would have resulted in new xorg.conf.
Step 2 => Removal of ati folder and xrog.confs.
Step 3 => Installing flgrx drivers afresh.
Step 4 => Generating new ati confs.
Step 5 => Rebooting and enabling desktop effects