Yes, I have always read that you should purge the driver first before installing a newer version. You can easily remove fglrx with this command- sudo apt-get remove --purge fglrx fglrx_* fglrx-amdcccle* fglrx-dev*
After you run this install the new driver then reboot and hopefully you'll boot into lightdm again. If you need any help let me know and I'll try to help.
Yes, I have always read that you should purge the driver first before installing a newer version. You can easily remove fglrx with this command- sudo apt-get remove --purge fglrx fglrx_* fglrx-amdcccle* fglrx-dev*
After you run this install the new driver then reboot and hopefully you'll boot into lightdm again. If you need any help let me know and I'll try to help.