You can't configure that within default software. 

You need to hide sign-in form inputs and sign-in buttons via css, that's the only solution that comes to my mind. 

Otherwise this is a custom code modification. 

Hello

I want to disable default login, when ever I enter site, it asks for login to every user.
I don't want every user to login. Guests should be able to view the brief profiile and for detailed view guest should create account.

Please help me to get away from it.
Urgent help required.

The only thing you can do for guests is to allow them to view the site by going to admin / settings / user settings selecting "Yes" next to "Guests can view the site"
Then go to user roles, and check the items for guests there. They do not have any options to interact; just view unless they become registered members.
Go to pages / manage pages, and make sure you have the pages set as viewable for guests.
I you need more than what the system is designed to do, you will need to hire a developer to do this for you.