prompted for a username and for a password when home networking

hello,

I had 2 pcs and 1 tablet. Recently i just bought another laptop and it's kind of weird whenever i tried to connect to other computers for files sharing , it kept asking me user name and password. It only happen on the new laptop that i just bought. Any idea how to get rid of the login screen i.e. user name and password. Thank u very much in advance for all the helps.