Try the following
<link rel="stylesheet" href="Code/jquery-ui.CSS" />
<script type ="text/javascript" src="Code/jquery-1.9.1.js"></script>
<script type ="text/javascript" src="Code/jquery-ui.js"></script>
<link rel="stylesheet" href="Code/Styles.CSS" />
OR
<link rel="stylesheet" href="/Code/jquery-ui.CSS" />
<script type ="text/javascript" src="/Code/jquery-1.9.1.js"></script>
<script type ="text/javascript" src="/Code/jquery-ui.js"></script>
<link rel="stylesheet" href="/Code/Styles.CSS" />