Are you using Internet Explorer 9 beta? If so, we do not yet support this version of Internet Explorer.
There are two things you can do to fix this:
1. Use another browser. Internet Explorer 8 and below are supported as well as Firefox and Chrome.
2. You can change your compatibility on Internet Explorer 9 beta. To switch to compatibility mode, press the F12 key. A box will appear. At the top of the box you will see Browser Mode and Document Mode. Change both of these to IE7. You can find an image of what you will find below: