This isn't quite related to webdesign but has security implications.
How do erase footprints leftbehind after you enter a username & password and/or criteria left in search engine?
An example: Username = "ABC....Z" Password = doesn't matter
If I enter in this in once, everytime I type "A" into the input box, "ABC...Z" shows up in a list below the input box of possible (remembered) usernames that I can select.
I've tried the whole Tools>Internet Options>Delete Files & cookies & history stuff... but that doesn't fix the problem.
If you want to clear them all, you can go to Tools>Internet Options>Content and choose Auto Complete. From there you can clear forms and/or passwords. You will also see how you can configure for future use.
Or, if you just want to get rid of one of them, while on a page, just select it when in the drop down, and hit shift/delete.