Troubleshooting for Internet Explorer (IE) browser users
When you use this site, you may get dialog boxes asking if you want to allow mixed content. You can change your IE settings so that you no longer get asked this every time you want to view a page.
In Internet Explorer, click the Tools button, and then click Internet Options.
Click the Security tab, and then click the Custom Level button.
In the Security Settings dialog box, scroll to the Display mixed content setting in the Miscellaneous section, and then click Enable.
Click OK in the Security Settings dialog box, and then click OK to exit Internet Options.
Restart Internet Explorer.
If you still get asked about mixed content, restart your computer.
These instructions come from Microsoft:
http://windowshelp.microsoft.com/Windows/en-US/help/16ee1fa9-60ab-4c1b-9b35-15b59a142f431033.mspx#E1