You need to completely un-install QuickTime. Completely un-installation mean that you have to remove other associated files with this and remove it from registry also. I would recommend to use a system cleaner tool like Reginout to fix registry errors and remove all unwanted files after un-installation of Quicktime. Hope problem is fixed.
Generally speaking, you can uninstall QuickTime by going to Control Panel - Add/ Remove Programs. After uninstalling it from Control Panel, do go to check whether it's completely removed or not. QuickTime has some specific files in the folder C:Program Files. If you find them, that means you haven't conducted a clean QuickTime removal yet. Then you can also try it with a uninstall tool.Go to the site from www.bestuninstalltool.com