There are other threads related to this question for Ubuntu 12.04, however THEY DO NOT APPLY TO 12.10. This is not a duplicate of another thread if the referenced thread doesn't answer the question ...
Black screen while booting, after installing AMD Catalyst™ 12.8 Proprietary Linux x86 Display Driver on HP pavilion dm4
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 ...