Disable Mouse Back Button

I have a Dell PC with Windows 8 and a Dell mouse with a button on the left side that functions as a back button. Accidentally clicking this button when in a browser is a pain so I want to disable that function.

Windows control panel > Mouse > Buttons tab > shows options for switching left/right, changing click speed and using click lock. Unlike Windows 7, there is no option for disabling specific mouse functions. Google on this topic did not find anything on Windows 8.

Henry