How much do grad schools care about my dismissal experience in my application?
without a single computer science course taken, I ... got admitted by Columbia University

If Columbia admitted someone who had never taken a course in CS to their masters degree in CS, I'd say they probably made a mistake.  A surprising one.  It's clear to me that the problem was

You did not know you were enrolling in a degree that is not for CS beginners
Columbia did not realize you were a CS beginner.
You are not a CS beginner any more, so this whole situation is no longer relevant.


does the grades in Columbia take into account for the overall GPA or the GPA's are seperated for each institution I've attended?

Each institution will compute its own GPA.  It would be unreasonable to combine them, as each university has its own grading system.

How much will admission committee care about the dismissal experience?

If you explain the circumstances (not prepared for the degree program) and what you did about them (second bachelors degree with good grades) then I think most admissions committees will consider your more recent grades to be more important.
You should seriously consider if you have any use for more degrees.  You might have enough already.