Thanks for your reply Scrooge.
I can't seem to find my mobo disk. May have lost it in a recent move. Do you suspect that SP1 may have disabled the drivers?
I got a reply from the vendor which simply says that no drivers are required for Vista.
I'm reluctant to uninstall SP1. This might cause more problems surely;

with my 8800GT drivers for example.
This is a bit of a disaster. Others must be getting this problem surely? I can't believe there isn't a workaround.I may contact MS as they are offering free support for SP1 related problems but if anyone knows a solution I would be eternally grateful.
Thanks, John