The easiest method is to try and remove the leftover by the software using a clean-up utility which searches the computer in all kinds of locations that are hard to navigate. One tool which does this is CCleaner. Beside its main function (cleaning) it also has the ability to uninstall applications, modify the start menu (which is required in your case to prevent the application to run) and many others. You can download the software and perform a registry cleanup because in 99 % of the cases that is the source of the problems.