This is a very common problem and I always forget the answer to it. If you need to log in to Drupal but you don’t have a “log in” button or link, you need to go this URL:
http://www.example.com/?q=user
Type in the ‘/q=user’ part EXACTLY as typed. Do NOT make the mistake I made, thinking ‘user’ is a placeholder for your user name and enter this instead:
http://www.example.com/?q=admin