Answer by 10robinho for Gnome Shell has turned into Gnome Classic (no effects) after installing fglrx.

Installing fglrx-updates and fglrx-amdcccle-updates fixed similar problem for me.

Don't forget to remove old fglrx first:

sudo apt-get purge fglrx*

then install

sudo apt-get install fglrx-updates fglrx-amdcccle-updates

and run

sudo aticonfig --initial

and reboot.

You should be able to run fglrxinfo and see output that confirms good installation.