I had the same problem this morning.  We made some changes yesterday that require you to reset your cookie.

1. Clear your browser Cache.

2. Go to the site registration page (http://www.myitforum.com/registration/), and login using your username and password, clicking the Edit Profile button.

3. In the Website Cookie and Forum Cookie sections, select 'No' for both and click the Select button.

4. Once the changes have taken place, log back into your profile (again, http://www.myitforum.com/registration/) and reverse the process.  (Choose 'Yes' for Website Cookie and Forum Cookie and click Submit).

5. Check your ability to navigate the site and post to the forums.

If you have any additional trouble, drop us a note (admin@myITforum.com), but this generally fixes any issues.  Cookies can sometimes become corrupted, get deleted, or not update properly due to local security settings.