How to connect to another PC? (Windows)

System / Administration / Share Folders -> set up folder sharing.

To reach your Ubuntu using laptop from a Windows you must set up a password for the Ubuntu.

I found the solution here.

It says:

sudo smbpasswd -a USERNAME
sudo /etc/init.d/samba restart

You should use your username, and it is preferred to give not the same password as your root password, because windows will store it.