Browser non-Responsive

Very frustrating situation: Afer a URL is typed into the Address field of IE, NOTHING happens. Hitting Enter, clicking Go are all ignored. Occasionally, it will navigate to the URL typed but only after nearly 2 minutes. Clicking on Favorites or links are no problem, it’s just typed URL’s.

XP Pro SP1; IE 6.0 and all current updates installed.

Any suggestions?