Once logged into blackboard, there is a table on the left side of the page that displays menu options such as "Announcements, Email, Course Content, and My Grades." If it is no longer there, it is likely that it has been accidentally hidden.
To unhide the menu, hover your cursor to the lefthand-most side of your page and a gray vertical bar should appear. Clicking on this gray bar should reveal your course menu.
For additional assistance, please refer to the following youtube video: http://www.youtube.com/watch?feature=player_embedded&v=9PpwjX8RCW4#!