Hi,
if you open the Task manager (right click on Task bar), look across the top for 'Start up' and click it. You'll then see a list of apps which start when Windows starts, simply find the app you want and disable it starting. It will still work if you click it but won't start automatically..
This is of course if you actually want to use the application if you don't then simply remove it from the Programs section. (uninstall it)