Check these keys for Intel chipset, set to 0 >HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Msahci >HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV Changing from RAID to AHCI, you may need one more step. Msahci driver requires Atapi.sys miniport to be loaded during boot as well. >HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\atapi For AMD chipsets >HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\nvstor >HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\nvraid >HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\amdsata (non raid)