Vista - CD rom not working

I bought a new computer from PCSmart (a "Simply KX-3100") a couple of weeks
ago. After the first update of Windows Vista, 2 days later, it lost access to
the CD player (a Sony DVD RW AW-Q170A). Vista indicates that the driver is
there but it cannot install it (error 39). I have tried everything to get the
CD rom back including:
1) Installing/Unistalling the driver and rebooting. 2) Removing Nero. 3)
Check that BIOS recognises the CD rom. 4) Get driver updates from MS Web page.
The answer from Vista is always the same: cannot install driver, error 39.
Can anyone offer a solution for this problem, it is driving me crazy!

Thanks in anticipation,

Augusto