I don’t think Apple ever wanted people to open the Mac Mini. Over the weekend my father in law and I installed memory in his and was it ever hard.
I did a lot of searching and Smash’s World has a video that tells you how to open the little machine. Just take a puddy knife (or two) pry it into the Mac Mini and basically force it open. I’m not sure how Apple intended people to get in and upgrade memory, but they sure didn’t do a good job of making it accessible.
Oh, and on a side note, there is only one memory bay?! What’s up with that? I guess they were conserving space, but I didn’t realize that until I opened it.
We didn’t break anything, or any plastic clips on the inside, however it sure wasn’t fun to open either. The G5 iMac, G3 & G4 PowerMac and PowerBook are all easy to open and install memory in, but the Mac Mini is extremely difficult.