Wow a luxury. They gave you double ball bearing fans AND they gave you an access hole covered by a sticker. These days you get a GPU, it has a rifle oil bushing and no more access. Such fans use a plastic snapring. You can just make your own out of a sheet of suitable plastic and a set of leather holepunches if you have them at hand, and just use a knife to slice an opening into it. Or you could make one with a sharp knife all alone, even if it turns out a little ragged.
