Hello, I very much hope that this community of experts may help to solve my problem. I have a Windows XP SP2 installation well functioning on an IDE HDD. For security reasons, I would now like to clean install a different copy of Windows XP into another partition on a SATA HDD within the same desktop PC. I want to get all the benefits of a SATA HDD within this second Windows install (i.e., not run it in legacy IDE mode), but I understand that I have to set the BIOS SATA mode to AHCI first and include SATA drivers into the Windows setup (F6) or the SATA HDD will not be recognized by the Windows XP setup. My question: will I be able to boot the first Windows XP installation on the IDE HDD after I have changed the SATA bios to AHCI to be able to boot the second install from the SATA HDD. Ideally, I should be able to chose among the two Windows installs within the Wndows Bootmanager and boot either of the two. Am I correct? I hope I have stated the problem clearly so that you may understand my problem. Thank you for your advice. I always share my knowledge where I am an expert, yet I have too much awe for a PC considering the days and months of my work stored on its HDDs.