HP Pavilion dm4 with configuration as shown below cpu intel Core i5 2.26 GHz RAM 4.0 GB Graphics processor 512MB ATI Mobility Radeon(TM) HD 5450 switchable graphics [HDMI, VGA]. I installed ubuntu 10.04 ( without AMD graphics driver) it was working fine, but when I installed AMD graphics drivers AMD Catalyst™ 12.8 Proprietary Linux x86 Display Driver, than the problem started from then When I boot I was get black screen. Than I thought to upgrade from ubuntu 10.04 to 12.04 using the bootable pen drive but was getting black screen than read on some forums that was because of the switchable graphics, than upgraded ubuntu 12.04 by setting to "nomodeset". It was working, again thought to install graphics driver AMD Catalyst™ 12.8 Proprietary Linux x86 Display Driver, again after installing this, when I boot I am getting blank scree . Can anyone help me to inatall ubuntu 12.04 along with AMD Catalyst™ 12.8 Proprietary Linux x86 Display Driver. Any help is highly appreciated.