The simplest is to run Fix It -> http://support.microsoft.com/kb/922976
Some MOBO's allow 'some' of the SATA ports to be IDE and others AHCI; it's best to have them ALL one way or the other. THEN go into the Registry or use 'Fix It' but be careful to ONLY change the Start = 0
and nothing else.
IF you accidentally created a corruption, the simplest 'fix' is to play musical SATA Ports with ALL the drives, be careful if there's a RAID and reboot. This causes ALL of the drivers to be re-installed and the Registry values re-written.