For slackware, I believe you need to login as user "root" and with no password (i.e. just press enter).
You should then look into creating a root password (by "should" I mean "definitely absolutely must") and a user so you can do as little as possible as root.
You should beware that slackware will be a steep learning curve for a *complete* noob - I'd recommend starting with a much more user-friendly distro like Ubuntu, or Debian if you're looking for something a bit more "techy". If you go ahead with Slackware, be sure to bookmark the slackbook and read at least the introductory chapters (http://www.slackbook.org/
), and consult when you want to know how to do something like set the root password or create a new user...