If you're using MS Internet Explorer click on "tools" at the top, then "internet options", select the "content" tab then "auto complete". If you now click on "clear passwords", hey presto, all gone.
Whilst you're there click on "clear forms" too. If you don't want others to see what you've been looking at on the net, select the "general" tab and both "clear history" and "delete temporary files" will erase your viewing history. Of course if you're a strictly business user this won't be necessary, will it?
Cheers
------------------
hhhiiisssssccrrrraaaacckkkllesssshhhhhh