Are you asking how you can keep those users out of your code?
If yes, inside the VBE, you can lock the project.
Tools|VBAProject Properties|Protection tab.
Give it a memorable password and lock the project for viewing.
If you're asking how to stop the users from interrupting your running code, take
a look at VBA's help for:
I should have added that protecting the VBA project will keep most out, it won't
stop the determined. There are commericial password breakers (pretty cheap) and
other free versions.