Download new ati
driver, driversweeper and CCleaner first
reboot Hit F8 just after last bios hard drive message and go into emergency start/'safe mode' and try and unload ati if prog lets you.
If it won't, uninstall the ati
driver and tell system to delete
driver(bung it on vga basic driver)in 'puta management.
After it does that go onto C:drive and delete the contents of the ati folder.
Start driversweeper and look for ati stuff - delete
Restart pc
do another ati-sweep then run CCleaner 'registry clean' and have a look if any debris is left (save a backup if you decide to clean registry)
Go back to 11.x and start driver/cat install process
Same is happening to me
(after the last two months of security updates - even got some extras today(thurs) after "download tuesday")
Computer has destabilised with mouse freezes and graphics causing loads of problems (can't update from 11.1 driver stably on AGP - new installs are stalling too)
Some games refuse to start after last months 'security updates' (including two popular M/Soft games)