Can't access network computer and its files

So basically When I'm trying to access a computer on my home network from another one, because I want to use the printer, it asks me for a username and password of that network pc.

But it doesn't have any password, when I power the other computer with printer attached to it, there's no log in window. Windows goes straight to the user's desktop.

What possible password could my network computer have?

It would help if you gave details like which OSes you are running.

The workgroup and usernames/passwords need to be the same on both systems.

If you are running XP, just enable simple file sharing.

ok thx