Once you're sorted, several forums that you can't currently see will appear, and it will completely change your MNFF experience. Two weeks seems like a long time to wait for results, but it's worth it.
If you're NOT trying to access via a mobile device and are still having problems, I recommend clearing out your cookies. In Firefox 4, you can do this by clicking the 'Firefox' tab on the top left of the browser window, hovering over 'Options', selecting the 'Options' in that menu. Click on the 'Privacy' tab, and finally on the link 'remove individual cookies'. From there, you can either find the 'mugglenet.com' cookies or just choose to Remove All Cookies. Either way, once you've done that, you will have to log in again, but it helps with the login issues.
For Internet Explorer 9, click on the Cog shape toward the top right of the browser window and select 'Internet Options'. Under the 'Browsing History' heading, click 'Delete...' You have the option of selecting only 'Cookies' to delete. Once that is done, it's probably best to restart the browser and trying to log in again.
If you're still having problems, try restarting your browser if you haven't already. If that doesn't work, then post in the Ask a Mod thread. There might be some sort of issue with your account that would need to be looked at by a coder person or whatever (I'm not too 'up' on tech speak). However, it's usually the case that clearing cookies solves most of these problems.
Sorry about the delay in reply. Since you're not sorted yet, your posts don't show up right away. By the time they do, the site doesn't recognise them as new posts anymore. If no one answers you after a few days or so, feel free to post again, just to make sure this hasn't happened to you. We're here to help . :)