The entire site relies on javascript, so if it's not working that's the first place I'd look. First, go tools->internet options->security, select Internet, click "default level," and use the slider to set the security at medium. You can use custom settings if you want, but under Scripting you'll have to make sure everything's either marked enable or prompt.
If that doesn't work, try an alternative browser, such as Firefox, before going any further to determine if this is a browser or system issue. If it works with Firefox, click here to download/run IEFix, and if it still won't work click here for instructions for repairing Internet Explorer. If it does not work with Firefox, try clicking here to download the Windows Scripting Engine, followed by a check of your security software, which may be blocking javascript as a precautionary measure.
Hope this helps,
John