Rollover image problem (Help me)

[killmesuicide]

im trying to make a basic image rollover i have tried all the ways but they all screw up on me, i cant get it to work, strangley as i was able to months ago but i forgot how. now nothing i do works.
this is the code for the one that i thought was most likeley to work but guess what ..still dosnt work.
someone please tell me what im doing wrong, or explain to me how to re write the whole thing, before i jump off a cliff in fraustration.



<!DOCTYPE html PUBLIC
"-//W3C//DTD XHTML 1.0 Strict//EN"
"DTD/xhtml1-strict.dtd">

<head>

<script language="Javascript">

<!-- Hide script from old browsers


if (document.images) {

enterm1 = new Image
enterm2 = new Image

enterm1.src="indexfi/enterm1.jpg"
enterm2.src="indexfi/enterm2.jpg"

}

else {

enterm1 = ""
enterm2 = ""
document.enter = ""

}


// End hidig script from old browsers -->

</head>

<body bgcolor="000000">


<div align="center">


<table border="0" width="370">


<tr>
<td>
<img src="indexfi/itc0r1.jpg" width="367" height="260" />
</td>
</tr>


<tr>
<td>

<img src="multipfi/sxbox.jpg" width="368" height="39" />
</td>
</tr>


<tr>
<td>
<a href="main.html" onmouseover=
"document.enter.src=enterm2.src"
onmouseout="document.enter.src=enterm1.src">

<img src="indexfi/enterm1.jpg" width="366" height="61" /> </a>

</td>
</tr>


</table>

</div>



</body>

</html>