Reloaded Win 2K from the Dell restore disks.  Everything fine.  Upgraded to A12 bios from A02.  System now cannot find primary hard drive or fixed optical drive.  Downgraded to A08 bios, but the problem persists.  I've already reseated the hard drive and optical drive several times with no success.  Again, everything was fine until the bios upgrade.  Just in case you are wondering, I upgraded the bios in anticipation of upgrading the box to Win XP Pro.  Any suggestions greatly appreciated.