SATA AHCI is not enabled before installing new system, and after installing system, start SATA AHCI and then start system. Then blue screen would occur, and fail to enter system.
Reason: Win 7/Vista disables AHCI driver (Msahci.sys), you must first enable SATA driver then you could change to AHCI mode.
To solve the problem, please before changing the SATA mode of the boot drive, enable AHCI driver in registry. For this, please follow the next steps:
 Exit all applications in Windows, open regedit, if “User Account control” dialog shows, please click “Continue”.
 Find and click the next registry item below:
 HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
On the right side pane, right click “Start” in the column “Name” and then click “Change”.
Type 0 to the text “Data value”, and then click “OK”. In the “File” menu, click “Exit” to close the REGEDIT.