Check if darn IE compatibility mode is on...

IE Compatibility Mode Detection

    <script type="text/javascript">
        $(document).ready(function() {
            // Fix placeholder for stupid IE8
            $('input, textarea').placeholder();
            
            var agentStr = navigator.userAgent;
            var mode;
            var isCompatON = false;
            if (agentStr.indexOf("Trident/5.0") > -1) {
                if (agentStr.indexOf("MSIE 7.0") > -1) {
                    mode = "IE9 Compatibility View";
                    isCompatON = true;
                } else
                    mode = "IE9";
            }
            else if (agentStr.indexOf("Trident/4.0") > -1) {
                if (agentStr.indexOf("MSIE 7.0") > -1) {
                    mode = "IE8 Compatibility View";
                    isCompatON = true;
                } else
                    mode = "IE8";
            }
            else
                mode = "IE7";

            if (isCompatON) {
                alert('This application does not work with IE Compatibility mode. \n Please disable before logging in.');
            }
        });
    </script>