If you get this system, either get 2 hard drives right away or don't plan on adding one later. Dell used some kind of strange removable hard drive bracket that snaps into place. The system has two internal hard drive bays, but only included one such bracket. If you keep systems in use as long as I do that's really going to bite you in the backside a few years on.
Update: I checked some Optiplex 960's and they have the same drive mounting hardware, but Dell did include the second bay's empty mount. I'll contact Dell and see if this was just an oversight and have it corrected. The warning still stands to open any recent Dell Optiplexes you own or purchase and make sure that you have all the drive holders the system holds to prevent future unwanted surprises.
Seeing as so many Google users are looking for this, I may as well lend them a hand. Here's a link to the Dell Optiplex 980 manuals.
