BleepingComputer.com: How Could I Uninstall Ascentive Performance Center Software In My Vista?

How could i uninstall ascentive performance center software in my vista?
i was downloaded this software from CNet.com (ascentive active speed). after finished installed, i was unsatisfied with my vista performance, that previously running smoothly to slow. so, i decided to uninstall the whole software program. but the software which is ascentive active speed leave its component called ascentive performance speed. i tried to uninstall this software program using uninstall function in system tools. but it doesn't work. every time when i tried to uninstall it, it will said "Setup.exe has stop working". until now the software could not uninstall, but the program still working well. please help, how could i eliminate this software from my pc?