The application is marked and believed to be malware. 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 that, try running AdwCleaner to make sure that there are no leftover rogue registry keys or toolbars in your system. You should run AdwCleaner a couple of times to make sure that your computer is cleaned perfectly from malware.