Bios not recognizing any hard drives

I replaced a hard drive in a system and booted fine to win 98. When I attempted to add a second drive as master I got a meesage that now none of the hard drives or cd-rom drives were detected. I detached the second hd drive and re-booted and still have the same issue. I went into the cmos and had the bios auto detect the drives and it still finds nothing. This is the 2nd pc on which this has happened. please advise on how to get the hard drives detected again. All the jumpers are set correctly.