Are you talking about a physical button or is it like you're having phantom clicks on the browser back button?
I have Premium Home Vista on my computer and use Microsoft Internet Explorer 8 for accessing Internet. Sometimes the back button inadverently activates. frequently I fill out forms or applications online and the button, without my clicking it, reverts back to point before I started to type. If I have not saved the text, I have to start over again. Is there a solution for this problem?