+ 0 Votes Are the drives in question IDE or sata or a mix of both?. Peconet Tietokoneet-217038187993258194678069903632 6 years ago If "IDE" make sure that one of drives are "master" and the other is "Slave". If "SATA", then the drive will get its own connection. In the bios make sure that the drive you want to boot from is located as the first drive in the list. Or take out your added drive and see if you can boot your computer as normal.Please post back if you have any more problems or questions. + 0 Votes Both drives are IDE quentincraig 6 years ago Both drives are IDE. I had them set up as Master for the old drive and Slave for the new drive and the bios saw the drives. Now the Bios does not see the drives or at least does not say so. Also tried disconnecting the new drive and now the BIOS does not see the old drive. + 0 Votes Start over with the basics. Iam_Mordac 6 years ago Take a deep breath, center your FOO and begin again. <BR>Re-check the hardware.<BR>Are the cables good?<BR>Are all the cables in correctly?<BR>Check the BIOS for an "Auto Config" setting. It may find the drive again by itself.<BR>Connect one drive at a time and try the "Auto Config" again.<BR>Connect one drive at a time and try changing the config to match your drive. <BR>You should be able to id the correct config from the drive label.<br>Do both drives spin up when you boot?<BR>Are the jumpers set correctly?<BR>Try using the Cable Select jumper on the HDD's when you get the BIOS to recognize them. <BR>The drive closest to the MB is the master, (or Disk0) so unless you change the boot order, that is the first one the system will try to boot from. <BR>Good luck and let us know what happens.