Try uninstall everything again, then make sure the ATI technology folder is deleted from program files, then right click my computer, click manage (this to double check), click device manager, look for your graphics card, has it a exclamation mark next to it? if not, right click it uninstall.
From then you must restart your computer and redownload this:
Automatically detect and install option and download
AMD Graphics Drivers & Software
Install it, now download this
Download CCleaner 3.15.1643 - FileHippo.com
install and run a clean, after this run a registry scan and fix all errors, give the computer another restart.
If anything it maybe conflicting with another program, I also get ATI crash errors sometimes, but I think that's because I use rivatuner for my fan speeds and I normally set them to 100% and after 40mins or so on MW3 it may crash once in a while, but I'm sure it's my rivatuner and it could be your case also just another program? it's a pain sometimes