Windows key + R to bring up run, type control to launch Control Panel, then go to programs and features and then you should see a list of your installed games and programs. To uninstall Installshield just left click on it and click on the uninstall button above the list, then follow the on-screen instructions.
Right click on the process and select - Open File Location - Uninstaller should be present there as well. If not, you can always stop the process and remove the folder manually.