Windows 7 Convert IDE Mode to AHCI Mode without reinstalling

1. Start regedit
2. Go to key entry

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\msahci

3. Look for the key “Start” change it from 3 to 0
4. Reboot the pc
5. Change bios to AHCI mode

Souces: http://bourlas.alloenablog.com/2011/01/09/how-to-enable-ahci-mode-for-windows-7-and-vista-without-format/
http://www.ocztechnologyforum.com/forum/showthread.php?73355-Change-from-IDE-to-AHCI-after-Installation