there is a way to turn on ahci after installing os.
1. Make a system restore point. in case it fails.
2. start regedit.exe
3. then go to
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
4. edit first row
(Standard) - REG_Z - (Set value to 0).
5.reboot and turn on ahci in...