I am the novice sister of the initiator of this thread.
I thank you for your assistance. I opened the tower for the first time

, located the HD and IDE cables. Actually, I took out the HD - guessing which one - then I saw HDD etched in the bay bracket! I need to write down how they are plugged into the drives.
The situation is the BIOS. I have an AOpen AX34-U MB. The manual for this board shows R1.20 BIOS - the System Resource Report shows Award Modular BIOS v6.00PG. The current HD is 13 GB and I want to install a 160 GB - as a slave or master.
With regard to the slave/master, I need to look at the IDE cables. I have a CD ROM, CDRW (separate units), Floppy and HD. It seems (during my peek) that all were in use. Hmm. There is an empty bay for an add-on. This computer was built for me - still a Pentium III.
I have formatted a computer from FDISK, installing Windows, Sound Blaster, CDRW, etc.; however, I have never installed hardware - actually, the hardware is easy - it is the software.