Look at the motherboard. Trace down where the other drive is plugged into. If it's IDE then it should say IDE1 or IDE2 or something like that by the plug. That will tell you what kind of drive it is and where it's plugged into. Then check the back of the first drive, it should be set to master or slave. If it's set to slave then set the second drive to master of the second IDE plug in the BIOS.