sound s crashes

Booting into my Vista partition has become hit and miss. Often I'll get the safe mode screen offering nromal or last known good options. If I get in, although the Soundmax seems to be working, I immediately get a pop-up saying the audio wizard could not start...well I never asked it to. If I click on Sound Devices the module appears but if I click on microphone it crashes and I get the blue screen saying windows has closed down to protect your computer. I was trying to set up speech recognittion. I can't get back into Vista at the moment - the progress bar appears and then just a black screen with nothing and my monitor/system goes to sleep. Pre-Vista checks using the Vista Upgrade Advisor told me that everything was good to go.
I've tried one repair install already.
-- Peter Toronto, Canada P4 HT D865GBF @ 3.0ghz 2.0gb DDR 450gb HD ATI Radeon 9550 Graphics Soundmax 4.0 Audio