Help, I need the sidewinder 4.0 software!!

I've got a USB Sidewinder pad that technically works, but won't do diagonals and a few other things. Someone suggested that I get the 4.0 version of the software, but it cannot be found, even on Microsoft's site. I have found a few 4.0 versions, but they're only for the joystick and/or wheel.

Does ANYONE know where I can find this updated driver,or maybe have the latest CD and would be willing to send it to me?

Thanks in advance.