It should simply click or latch on. Read the instructions. If you still have a problem, ask some of the AC Freezer 64 owners here, if there are. Or look up guides.
It also shouldn't be a problem installing with the motherboard already in. And you really can take the motherboard out of the case, it's just you don't want to.
It also shouldn't be a problem installing with the motherboard already in. And you really can take the motherboard out of the case, it's just you don't want to.