I have a Mac Pro 5,1 with 2 genuine Apple (not-flashed) Radeon HD 5770 graphics card crosslinked. I am running Windows 7 64-bit SP1 under Boot Camp. After installing Windows, I installed the Apple Boot Camp drivers 5.1.5621. Unlike other Boot Camp drivers (such as 4.0.4033 or 5.0.5033), 5.1.5621 has ATI Catalyst Control Center. However, whenever I tried to start ATI Catalyst Control Center, I get an error message "Catalyst Control Center cannot be started... There are currently no settings that can be configured using...". I have .Net Framework 4.5 pre-installed and Visual C++ 2012 prerequisites already installed. What went wrong? Help!