How to turn on AHCI mode for Windows 7

The instructions on the computer's motherboard support AHCI mode , but since I installed Windows 7, I did not enable the motherboard's SATA AHCI mode, and then enabled AHCI mode after installing the system, resulting in a blue screen when Windows 7 started and no access to the system. Is there a way to open AHCI mode without reloading the system?

　　A : that's because you're like you did before. After you install Windows 7, the AHCI driver is disabled and you must enable SATA drivers before you can switch to AHCI mode. Before changing SATA mode, you need to enable AHCI mode in the registry first. To do this: Open Registry Editor (run Regedit) and navigate to:

Hkey_local_machinesystemcurrentcontrolsetservicesmsahci

Double-click Start on the right, type 0 in the Value data box, and then click OK and close the registry. At this point you can reboot the system and turn on SATA AHCI mode in the BIOS, and start win 7 will not be blue screen.