http://www.neowin.net/news/neowin-guide-how-to-change-from-ide-to-ahci-without-reinstalling-windows
- Run the Registry Editor (regedit.exe)
- Navigate to Registry Key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
- Set the “Start” value to 0 (zero)
- Navigate to Registry Key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Pciide
- Set the “Start” value to 0 (zero)
- Shut down
- Start up again, but before Windows boots go into the BIOS configuration screens and change the disk mode to “AHCI”. Save the new BIOS configuration and restart so that Windows boots.