<style type="text/css">
#part1,#part2,#part3,#part4 {
z-index: 2;
position: absolute;
visibility: hidden}
</style>

в html-низ:

<script language="javascript">
function part1on() {document.getelementbyid("part1").style.visibility='visible'}
function part2on(){document.getelementbyid("part2").style.visibility='visible'}
function part3on(){document.getelementbyid("part3").style.visibility='visible'}
function part4on(){document.getelementbyid("part4").style.visibility='visible'}
function part1off() {document.getelementbyid("part1").style.visibility='hidden'}
function part2off(){document.getelementbyid("part2").style.visibility='hidden'}
function part3off(){document.getelementbyid("part3").style.visibility='hidden'}
function part4off(){document.getelementbyid("part4").style.visibility='hidden'}
</script>

в обьявление

<a href="" onmouseover="part1on()" onmouseout="part1off()">линка 1</a>
<a href="" onmouseover="part2on()" onmouseout="part2off()">линка 2</a>
<a href="" onmouseover="part3on()" onmouseout="part3off()">линка3</a>
<a href="" onmouseover="part4on()" onmouseout="part4off()">линка 4</a>

<div id="part1" class="container">
контейнер номер 1
</div>

<div id=part2 class="container">
контейнер номер 2
</div>

<div id=part3 class="container">
контейнер номер 3
</div>

<div id="part4" class="container">
контейнер номер 4
</div>