Turn the logic the other way around: hide the element by default and reveal it with JavaScript.
<style type="text/css">
#accessButt { display:none; }
</style>
<noscript>
<div class="conB" style="margin-left: 3px;"><a class="fancybox" href="accessebility.html"> Accessibility </a></div>
</noscript>
<div id="accessButt">
<div class="conB" style="margin-left: 3px;"><a class="fancybox" href="#accessebility">Accessibility </a></div>
</div>
<script>
document.getElementById( 'accessButt' ).style.display = 'block';
</script>