So, about those little drop-down things that remember your email for you as you're typing it in...?

On Internet Explorer there is a "tools" tab around the top right corner and on Google Chrome there is a wrench icon located also around the top right corner that you can go to and click on the relating choice(history, options, etc..) and you can delete your browsing history, cookies(which is what you probably need to delete for your issue), and things like that. On firefox in the top left corner there is an orange rectangle at the very top left corner that says firefox, click on that rectangle and it will give you choices to choose from.