You made the change in the BIOS, but Windows 7 just gives you the blue screen of death (BSOD) at startup. You may have even tried to boot from your Windows disk and run startup repairs. No success, no joy. Windows could not make the repair.

You may have been told you had to return BIOS to IDE mode for the drives. You may have been told a re-installation of Windows 7 was required. Here is how you can fix this issue and derive the benefit of AHCI drivers on your SATA drive.

By design the MSAHCI driver in Windows 7 is disabled if the original install was made with the BIOS set to native IDE. This is done to speed boot up time by not loading unnecessary drivers during the bootup process. The MSAHCI driver must be enabled before you change the IDE/AHCI mode of the boot drive.

For detailed information, see http://support.microsoft.com/kb/922976.