Macbook running vista 32 bit - no audio

I've just loaded Vista on my MacBook (Leopard) using Boot Camp and all is working fine except for the audio. I get an error saying that Windows cannot initialize the device driver (Windows error 37) for Cirrus Logic CS4206A (AB31) device. I've tried disable/enable, re-installing the driver from Boot Camp and searching for a new driver (it says its the most up to date). I've run out of ideas. Can anyone give me some suggestions?

Thanks!

What does the Windows Device Hardware Tree identify your sound as? It may be that the wrong driver is installed. According to windows\system32\drivers the driver I have listed for Cirrus is "circlass.sys". You can check that file by right clicking on it and select properties. Read what it says.

Also, you might try loading Vista in Safe Mode to see if that helps. Hold down the F8 key when Windows starts to boot.