Doum said:
Have you tried this yourself?
I have always read that AHCI drivers have to be installed at the same time
than the OS. (F6 when XP installation start).
You can change the controller drivers anytime after Windows is
installed, manually install the AHCI drivers from within Windows then
reboot, that is all there is to it. You will only have problems if you
change the BIOS settings without first installing the drivers. Perhaps
you're thinking of Non-ACPI/ACPI Hals which cannot be changed after
Windows is installed, that is a different thing altogether.
John