If a user cannot see the modules that they have access to under Company/User rights/Administrate users then this is due to the fact that they have profiles or fixed profiles set up. Read more about profiles here (Use chrome translate).
Fixed profiles can be selected using the 'Fixed profiles' button under Company/User rights/Administrate users. A user can be set up with a fixed profile of 'None', Invoice' or Time registration' here.
FIXED PROFILES CANNOT BE BLANK. Otherwise the user will not be able to see ANY modules. Set the fixed profile to 'None' in order for the user to be able to see the modules that they have access to.