I'm running Windows 7; downloaded newest version of Firefox from mozilla web site; ran .exe; shortcut icons show up on desktop and task bar; but Firefox will not run when I try to open it via the shortcut. Tried opening as administrator; checked to be sure no other programs were open or running; rebooted computer several times; nothing worked. Moreover, I cannot find the actual Firefox application anywhere on my machine, so it appears that the application does not fully install. So need help! Thanks.