Vista Audio Driver installation

I have installed vista ultimate onto my computer and I need to install a driver for my speakers. The problem is every time I boot vista automatically installs drivers for hardware which is missing it and the one it installs does not work. I think i may need to uninstall the driver and then reboot and install my own (realtek hd audio driver for windows vista) however I cant Because every time I boot it automatically installs its own driver again. I have turned windows automatic updates off, this didnt work.
Does anyone know how to disable automatic driver updates or can help me install a driver that works.