some basic config explained here: http://lani78.wordpress.com/2008/08/08/generate-a-ssh-key-and-disable-password-authentication-on-ubuntu-server/
now for the dummies (me):
copy the created public key (ends with .pub) to the authorized_keys file (in ~/.ssh dir). there is one line for each key in this file and the file is not there event after running ssh-keygen. needs to be created..
this key needs to be converted with puttygen to be usable.. then configure it in the ssh->auth setting in putty to set the login file. blaablaa gave up at this point and disabled my stuff