Try using Revo Uninstaller. Even if it can't uninstall the application normally, it will force it to uninstall by wiping out all traces of its presence from the system.
After Revo finished uninstalling the application, reboot the computer and run a copy of Combofix. During the scan, Combofix will turn off the Internet connection and close all the background applications to increase the speed and compatibility. The computer might restart a few times during the installation.