Well, their setup for obtaining your user name and resetting your password seems easier and more clear than many.

Follow the login link on the upper-right corner of the page. Click the link that says "forgot your password?" Enter your user name or the e-mail address you used to sign up with Spotify, and "submit." You'll immediately get an e-mail with your user name, along with a link that will allow you to reset your password.

This all seems easy to me, but maybe your problem is more complex. If you already have your user name an password, try a "disk cleanup" if you have a Windows computer. That may remove something that not allowing you to log onto Spotify.

-Joe-