I downloaded McAfee SiteAdvisor. I had the icon but I don't know what happened to it? It is still in my Control Panel,how can I get it back to the top of my computer's browser window so I can use it to check if other sites are Safe?
You've probably removed its icon. Right click on your tab's empty space inside the browser then select Customize. Scroll down and then drag the icon back to its original place. You can do this for almost all browsers.
