No worries. Simply click Login and then click the "forgot password" link. Enter either your username or e-mail address that you used when you first registered, select the appropriate radio button and press submit. A new password will be e-mailed to you.
Note: Once you get your new password and log on, edit your profile and change your password to something that makes more sense to you and that you'll remember.
Also, If you originally filled out the Ask Me A Question box in your Profile, you can also select this check box which will prompt you for the answer. If you enter the correct answer you may change your password immediately without having to get a new one e-mailed to you.