It is very hard to understand what you wrote. However, this block I understand enough to answer.
Quote:
when I host the website if one user make something which cause website stop will also affect the other user. or different instances are created for different user or session after hosting website
If the website crashes then all of your sessions will be lost, unless you are using a different mode of session than the default. See
Session-State Modes[
^]
If a user's browser crashes and not IIS then only that user is affected. In fact, their session will still be active on the server because the server has no idea that the client crashed.
It all depends on how you setup IIS.