I found the solution.

After downloading several drivers that would not load because the
install app said they were either not for this model or not for
this OS, I found the answer he
http://social.technet.microsoft.com/Forums/en/w7itprohardware/thread/0b4956dc-9fc8-4e63-bbde-c50fd44cda1e
or
http://tinyurl.com/yhz59rn

I found the Sony Alps Pointing Device Update 7.0.501.5 for Vista,
and it loaded successfully on this machine.

I suspect that the critical factor was that the update was for an
"FZ" model of Sony Vaio.

--
Dave
Sony Vaio VGN-FZ320e