Rafmag,
Here's another thought for you. If your W2K was on a second hard drive before (anything but the C: drive), it doesn't actually contain the boot files. No matter how many OS's, drives or partitions you have on a system, the boot files for any OS need to be on the C: drive. That's where the Master Boot Record is. So if you're trying to boot to a drive/partition that was formerly not the C: drive, it won't work even though you may think you installed W2k there. Only the GUI files were put there. Make sure your new setup includes the drive that was your C: drive before in the Master position on the ribbon cable, properly jumpered, and put the second hard drive in the Slave position on the cable, properly jumpered. Otherwise, you'll have to replace the system files on the W2K drive. Make sure all connections are nice and snug (power and ribbon cable).
Drew