Can I simply run cvx_setup again and again (even though setup has been already done) in MATLAB Windows PC? It will not affect any CVX or other right?
And also, in case, if MATLAB is used after long time or restarted, then is setup is need to do using cvx_setup command or no need?
You can run cvx_setup as many times as you want. Unless something has changed or gotten corrupted on your computer, or you want CVX to find a newly installed or updated solver, there should be no need to re-run cvx_setup, no matter how long since you previously ran it.