Yamaha psr e403

Wow, this site actually works, that's cool. 
Well, truth be told, I aborted the mission.  I tried everything I knew how.  I'm fairly savvy w/music gear, as I produce my own music in my studio here.  I just couldn't get the driver to install.  Granted, I'm new at Vista and it's my wife's kickaround PC, so I didn't bother getting to the bottom of it.  
My gut feeling, however, is that there is an answer.  I don't know if it's a problem with Vista or the software.  Yamaha might have a customer service number.  Perhaps the vendor you bought it from?  I buy all my gear from Sweetwater and their free tech support is worth every penny I spend there.  
I have no answer for you, unfortunately, but as someone who deals with tech issues regularly, I know that the answer is out there for you.  
Best of luck,
hanaleiheart