I FINALLY figured it out. I don't really know why though.
I randomly searched google for reinstall vista sigmatel.
I got a page of:
http://kumaryu.wordpress.com/2007/02...manufacturers/
and went to
http://search.dell.com/results.aspx?...sta%20sigmatel
clicked Verify Operating System and Product Compatibility to find out which driver was for my computer ( R147073.EXE is for the M1710 )
it asked me to restart and i walked away for a minute. In the background I heard vista starting up. Finally I have sound again! Hope this helps anyone in the future having problems with Vista Ultimate and Sigmatel !