Is there a way of shutting down some or all the fans when the system is in
standby? I used to have this working in Win XP using the S3 power state. The
powercfg reports that only the (S3) Hibernate hybrid sleep state is
available. I've had a look in the advanced power options but can find
nothing there which might help me.

The motherboard is an ASUS P5AD2 Deluxe and I have S3 enable in the bios