ASUS notebook hard drive question

Hi

I picked up an older model ASUS notebook at a garage sale. It's in perfect condition and looks like it's hardly been used. The problem is, the hard drive has been removed. It looks like the HDD would have been mounted in a carrier or caddy with some kind of interface connector to the motherboard. That part is missing and I'm not sure what it is or what it looks like.

I've been all over the ASUS website and on the phone with tech support trying to identify the part and purchase one. The support people are polite but seem absolutely clueless.

The notebook is barebones ASUS Model S1N (About year 2003 or 2004)

I would surely appreciate an input from anyone with experience in this area.

Thank you,
Doug