Browser Buttons opens Search Function

Hi,

I have just purchased a refurbished kindle 3. I am unable to turn the page beyond page 2 on any book, as the browser buttons, left and right, opens up a search box and enters random characters into it. Whenever I press the right browser button it does not turn the page, but enters "45" in a "find on page" box. Same for the left button, only it enters "354".

I have tried hard, and soft factory resets, and the problem persists.

This is very frustrating problem as, if I unable to turn the page, it renders the kindle useless.

Has anyone encountered this problem before, and is there a solution?

Thanks.