On Thursday, I upgraded Ubuntu from LTS 12.04 to 14.04 LTS, Its been 2 days juggling up to restore my laptop to normal, I have exhausted nearly all suggestions listed on Ubuntuforums, IRC, Askubuntu ,other Internet sites,
but to no rescue I am at same page. Please suggest some measure in order to restore the Ubuntu 14.04 LTS to normal or 12.04.

I am using Toshiba L640, i5 core 2 Duo, ATI Radeon 5145 graphics inbuilt with Intel chipset board. Earlier I was using Ubuntu 12.04 with gnome-fallback desktop environment, FGLRX was working fine with cairo dock, though 2 months back there was some problem with fglrx graphics driver, I did not removed it and continue working on 2D gnome-desktop environment. I thought to upgrade via update manager, hence I did update, All went well but when the system rebooted, It never started again as normal. On using old kernel same problem is appearing and when I tries to login by CTRL+ALT+F1 /(F1-F6) login screen dont accept default username and password, hence I am not getting idea how to restore back as it stucked in login loop.

I know last solution is to take backUp and use fresh Ubuntu 14.04 installation and install everything on that again. Apart from this is there MEASURE to solve the graphics display problem, login screen problem back to normalcy.

Working suggestions and help will be much appreciated.