If you encounter a blank page when you try to log in but you can see the site just fine you may resolve it by clearing the browser's cache and/or updating java on your computer.

To clear the cache please visit this University of Indiana page that addresses a variety of browsers, with screenshots: http://www.wikihow.com/Clear-Your-Browser%27s-Cache

To see what version of  Java you have and some details about it, visit this link: http://java.com/en/download/installed.jsp and click on the 'Verify Java Version' button.

If Java is out of date that page is the right place to be and it can help you to update Java on your computer.