In the past year or so, Stack Overflow has tended to require more and more that questions be directly related to coding; there is a general expectation that a question should involve source code, or directly ask how to write source code to perform a specific task. Questions of a more “whiteboard” nature, such as those concerning algorithms and data structures, tend to be sent away to the Programmers Stack Exchange site. Questions related to the theory of programming are touch-and-go on either site (they're officially on-topic, but they often get closed or ignored), even when they stray pretty far from mathematical models into the realm of software design.
There is currently a proposed Stack Exchange site for computer science, which would cover theoretical and applied aspects alike, at all levels. I invite everyone interested in computer science to commit to this proposal.
On every site, questions are expected to follow the Stack Exchange guidelines, which prohibit questions that require extended discussion (“not constructive”), are too broad, or are rants disguised as questions. Among your examples, #1 would be both off-topic (it's about computers, not about programming) and not constructive, #2 would be ok if enough details are provided, #3 would probably be sent to Programmers (or rejected as non-constructive, depending on how much detail the question includes), #4 and #5 would likely be rejected as too broad due to the lack of effort demonstrated by the asker.