I tried to open Firefox and a message appeared: "Couldn't load XPCOM". I uninstalled the program with Revo Uninstaller Pro and downloaded the latest version. I selected Run as Administrator but there is a message that says "Windows cannot have access to the selected device, path or file. Maybe you don't have access rights". However, I do have access rights. I have checked it multiple times. How can I install Firefox and see it work properly? Thanks