uninstall all video drivers and run a registry cleaner.. CCleaner is ok, but only does a quick scan, my fav. is TweakNow RegCleaner.. this should take about 10min. Delete anything with the contents of ati in them. Restart and run the install.
I've found that newer versions of mobile drivers just dont install the necessary drivers properly. I went through all up-to-date versions of Catalyst (from 11.12 downwards) and have finally settled on 11.8 as the driver version that works with my HD4650M
ATI, on paper, may have the best chips but they really do suck at making drivers. I used to have a mobility Nvidia chip and that always worked perfectly upon compatibility and new driver installs. Plus you cant do any real scientific computing with ATI chips as there's little to no support for OpenCL.