Since you are not posting this query on the spoiler board, I assume you just want hints and general guidance, rather than something that might ruin your individual quest of discovery. With that in mind:(1) As far as is known, you will never be able to access those computers, but feel free to keep trying. Who knows? Maybe YOU will be the one to discover something no one has tried before.
(2) There IS a way to get into that glass case (and to reach a number of other treasures "under glass" in the Upper Monastery. Keep looking around and trying things. Mild hint: this is a problem that can be solved within the Upper Monastery.
(3) The microwave chip has its own uses, although it is not essential to completion of the game. Mild hint: got gadgeteer?