Some more info:
1) I assume u have installed Windows Vista or Windows 7 with AHCI set from BIOS !
2) [Add keys from 3 if they don't exist)
3) Now the manually regedit part Go to :
And in thease three keys in the right pan u will find a key named "START" change at all three (Msahci,iaStor,iaStorV) values from 0 To 1
Now navigate to HKEY_LOCAL_MACHINE_System_CurrentControlSet_Services_PciIde
,then change the start value to "0"
4) Now u are allmost done , restart your computer/laptop , and go to Bios and set from AHCI to IDE !!! , save settings in Bios and restart
Solved Switch AHCI TO IDE (Tutorial HowTo) !!!