I forgot to say - if I try to put the m/c into standby after a bootup without 'disabling' + 'enabling' the drives I get:-
"The device driver for the 'HL-DT-ST DVD-ROM GRD8162B' device is preventing the machine from entering standby. Please close all applications and try again. If the problem persists, you may need to update this driver."
If I then 'disable' and 'enable' just the GRD8162B the error message appears but refers to the sony drive.
Anyone know which part of the startup sequence handles the ATAPI device detection and drivers?