Your Web Browser is a lot like a car - occasionally it will require some maintenance to ensure it runs how you would like it to. Below are some links to some guides to help you maintain your Browser of choice - navigate from there to the relevant support article.
First, you will need to know what Web Browser you are using. If you are unsure which Browser you are using click here.
How to Clear your Mozilla Firefox Web Browser History
How to Clear your Google Chrome Web Browser History