Are you setting up a new system? If so, put the drive on sata_0 of the main controller (assuming you may have more than one controller). If you are going to install XP, I recommend IDE mode in the bios. If it's windows 7, I recommend AHCI. Install the OS with just the one drive attached, other than the CD/DVD taht you will need to install from. After completeing the install, connect the remaining drives if you have any. If those drives aren't seen in windows, you will need to go into disk management and initialize the drives then they will show up.