How do I disable the Forward & Backward keys/mousebuttons?

I have a mouse with 4 side buttons. Those 4 buttons (Button4/Button5/Button6/Button7) are mapped to MB4, MB5, MB6, and MB7 in the configuration software, and they work as expected.

My problem is that although Button4/Button5 are mapped correctly to the inputs MB4/MB5, they are also mapped to Forwards/Backwards. I often use MB4 and MB5 as my push-to-talk key in VoIP programs for hours at a time. This makes it impossible for me to efficiently browse through folders in Win7 while simultaneously talking, since pressing MB4 or MB5 changes the folder that is open in Windows Explorer. As far as I can tell, it is impossible to disable this Forwards/Backwards function using the software that comes with my mouse--I have noticed the same is true of many other mice and mouse control software.

I don't need the Forwards/Backwards buttons to work on my keyboard, mouse, or any other device. How can I force Windows to ignore all the Forwards/Backwards inputs from devices?

Doesn't it change functionality if you create a profile for the browser exe? Or if you don't use those buttons for push to talk, then assign some non functional key.
You can also read about AutoHotKey or AutoIt (not sure of this one)