Heres what i do. Always works perfectly.
1) Uninstall ALL ATI software (drivers, control panel, hydravision, ect

Without rebooting between each uninstall.
2) Reboot into safe mode (Hold F8 on startup)
3) Delete the following directories:
C:\ATI
C:\Program Files\ATI Multimedia
C:\Program Files\ATI Technologys
C:\Program Files\Common Files\Raviscent Shared.
**You may not have all of the above.
4)Delete everything in:
C:\Windows\Temp
C:\Temp
**You may not have all of the above.
5)In the below listed directories;
Go into detail view, right click on the header, and click the check box for company. Then double click on the new header that says company, and when the Computer has finished sorting them by company, delete any that is related to ATI.
C:\Windows\System32
C:\Windows\System32\Drivers
6) Run Reg Cleaner, delete any ATI enteries(checking what you are deleting, cos searching for ATI also brings up other stuff in regcleaner, such as the creative drivers, which if you have a creative card, will want to keep).
7) Run Driver Cleaner, Set to remove ATI stuff, and remove.
8) Empty Recycle Bin
9) Reboot into normal windows, and close all background programs (firewalls, anti-virus`s, ect

. The install the following in the below order.
Install New Drivers
Install New Control Panel
Install other ATI software.
Its very similar to the rage3d guide, but with all the "crap" removed from it.