I have this menu which works fine in firefox etc but just will not work in I.E 7 can anyone tell me why?

<html>
<head>
<title></title>
<style type="text/css">
#mainmenu{
 width: auto;
 height: 30px;
}
#mainmenu{
 margin: 0px;
 padding: 0px;
 z-index: 1;
}
#mainmenu li{
 float:left;
 position:relative;
 width: 140px;
 border: 0px solid #fff;
 list-style: none;
 background: #336699;
 font-family: verdana;
 font-weight: bold;
 font-size: 14px;
 padding: 3px 10px 3px 10px;
}
#mainmenu li a{
 background: #336699;
 text-decoration: none;
 color: #000;
}
#mainmenu li a:hover{
 color: #ff0000;
}
#mainmenu li ul{
 display:none;
 position:absolute;
 margin: 0px;
 width: 140px;
 padding: 0px;
 list-style: none;
 top: 20px;
 left: 0;
 z-index: 2;
}
#mainmenu li:hover ul {
 display: block;
 width: 140px;
}
#mainmenu .drop {
background: #fff;
border-left: 1px solid #000;
border-right: 1px solid #000;
border-bottom: 1px dashed #000;
}
#mainmenu .drop a{
background: #fff;
}
#mainmenu .dropb {
background: #fff;
border-left: 1px solid #000;
border-right: 1px solid #000;
border-bottom: 1px solid #000;
}
#mainmenu .dropb a{
background: #fff;
}
#mainmenu .dropt {
background: #fff;
border-top: 1px solid #000;
border-left: 1px solid #000;
border-right: 1px solid #000;
border-bottom: 1px dashed #000;
}
#mainmenu .dropt a{
background: #fff;
}


</style>
</head>

<body>
<div id="mainmenu">
	<li>
		<a href="#">MENU 1</a>
		<ul>
			<li class="dropt"><a href="#">DROP DOWN 1</a></li>
			<li class="drop"><a href="#">DROP DOWN 2</a></li>
			<li class="dropb"><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
	<li>
		<a href="#">MENU 2</a>
		<ul>
			<li><a href="#">DROP DOWN 1</a></li>
			<li><a href="#">DROP DOWN 2</a></li>
			<li><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
	<li>
		<a href="#">MENU 3</a>
		<ul>
			<li><a href="#">DROP DOWN 1</a></li>
			<li><a href="#">DROP DOWN 2</a></li>
			<li><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
</div>

</body>
</html>

I believe the reason for this malfunction is because they don't support li:hover, so downloading that behavior is probably your best bet.

I resolved the problem a much easier way I.E 7 requires that you have a doc heading or it will not work I just simply added

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 4.01 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

and it works fine in both I.E and Firefox but now I have a new problem I have added a flyout menu it works fine in I.E 7 but not in Firefox?? I just tried this one with the behaviour htc and that doesn't work. :(

any ideas?

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 4.01 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title></title>
<style type="text/css">

#mainmenu{
 width: auto;
 height: 30px;
}
#mainmenu{
 margin: 0px;
 padding: 0px;
}

#mainmenu li{
 float:left;
 position:relative;
 width: 140px;
 border: 1px solid #000;
 list-style: none;
 background: #336699;
 font-family: verdana;
 font-size: 14px;
 font-weight: bold;
 text-align: center;
 padding: 3px 10px 3px 10px;
}
#mainmenu li a{
 background: #336699;
 text-decoration: none;
 color: #000;
}
#mainmenu li a:hover{
 color: #ff0000;
}
.nav1{
width: 140px;
margin: 0px;
padding: 0px;
}
#mainmenu li ul.nav1{
 display:none;
 position:absolute;
 list-style: none;
 top: 23px;
 left: 0;

}
#mainmenu li:hover ul.nav1{
 display: block;
 width: 140px;
}

#mainmenu li ul.nav1 li {
 background: #fff;
 text-decoration: none;
 font-size: 11px;
 font-weight: none;
}
#mainmenu li ul.nav1 li a{
 background: #fff;
 text-decoration: none;
 font-size: 11px;
 font-weight: none;
 color: #000;

}
#mainmenu li ul.nav1 li a:hover{
 color: #ff0000;
}

#mainmenu li ul.nav1 li ul.nav2 li{
 font-size: 8px;
 font-weight: none; 
 color: #fffab8;
}
#mainmenu li ul.nav1 li ul.nav2 li a{
 color: #000;
}
#mainmenu li ul.nav1 li ul.nav2 li a:hover{
 color: #ff0000;
}


#mainmenu ul.nav1 li ul.nav2{
 display:none;
 position:absolute;
 list-style: none;
 top: -1px;
 left: 120px;

}
#mainmenu ul.nav1 li:hover ul.nav2{
 display: block;
 width: 140px;
}

</style>
</head>

<body>

<div id="mainmenu">
     
	<li>
		<a href="#">MENU 1</a>
		<ul class="nav1">
			<li><a href="#">DROP DOWN 1</a></li>

            <ul class="nav2">
			<li><a href="#">FLY OUT 1</a>
			<li><a href="#">FLY OUT 2</a>
            </ul>
			<li><a href="#">DROP DOWN 2</a></li>
			<li><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
	<li>
		<a href="#">MENU 2</a>
		<ul class="nav1">
			<li><a href="#">DROP DOWN 1</a></li>
			<li><a href="#">DROP DOWN 2</a></li>
			<li><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
	<li>
		<a href="#">MENU 3</a>
		<ul class="nav1">
			<li><a href="#">DROP DOWN 1</a></li>
			<li><a href="#">DROP DOWN 2</a></li>
			<li><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
</div>

</body>
</html>

In order to get this work in both i.e and mozilla i have gone and got my document to validate 100% on w3c org to their validation standatds problem is i have had to add an additional set of <li> tags which is creating an unwated list element but without it doesn't work in both browers. Can anyone think of a fix for this?
here is my code it is obvious that where the list is doesnt make sense but it valitates therefore the menu works but not properly because of the additional space???

validates in html and css without the opening <ul> tag doesn't validate I am lost here.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" >
<title></title>
<style type="text/css">

#mainmenu{
 width: auto;
 height: 30px;
}
#mainmenu{
 margin: 0px;
 padding: 0px;
}

#mainmenu li{
 float:left;
 position:relative;
 width: 140px;
 border: 1px solid #000;
 list-style: none;
 background: #336699;
 font-family: verdana;
 font-size: 14px;
 font-weight: bold;
 text-align: center;
 padding: 3px 10px 3px 10px;
}
#mainmenu li a{
 background: #336699;
 text-decoration: none;
 color: #000;
}
#mainmenu li a:hover{
 color: #ff0000;
}
.nav1{
width: 140px;
margin: 0px;
padding: 0px;
}
#mainmenu li ul.nav1{
 display:none;
 position:absolute;
 list-style: none;
 top: 23px;
 left: 0;

}
#mainmenu li:hover ul.nav1{
 display: block;
 width: 140px;
}

#mainmenu li ul.nav1 li {
 background: #fff;
 text-decoration: none;
 font-size: 11px;
}
#mainmenu li ul.nav1 li a{
 background: #fff;
 text-decoration: none;
 font-size: 11px;
 color: #000;

}
#mainmenu li ul.nav1 li a:hover{
 color: #ff0000;
}

#mainmenu li ul.nav1 li ul.nav2 li{
 font-size: 8px;
 color: #fffab8;
}
#mainmenu li ul.nav1 li ul.nav2 li a{
 color: #000;
}
#mainmenu li ul.nav1 li ul.nav2 li a:hover{
 color: #ff0000;
}


#mainmenu ul.nav1 li ul.nav2{
 display:none;
 position:absolute;
 list-style: none;
 top: -1px;
 left: 120px;

}
#mainmenu ul.nav1 li:hover ul.nav2{
 display: block;
 width: 140px;
}

</style>
</head>

<body>

<div id="mainmenu">
     
<ul>	
      <li>
		<a href="#">MENU 1</a>
		<ul class="nav1">
		<li><a href="#">DROP DOWN 1</a></li>
<li>
           <ul class="nav2">
			<li><a href="#">FLY OUT 1</a></li>
			<li><a href="#">FLY OUT 2</a></li>
            </ul>
</li>
			<li><a href="#">DROP DOWN 2</a></li>
			<li><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
	<li>
		<a href="#">MENU 2</a>
		<ul class="nav1">
			<li><a href="#">DROP DOWN 1</a></li>
			<li><a href="#">DROP DOWN 2</a></li>
			<li><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
	<li>
		<a href="#">MENU 3</a>
		<ul class="nav1">
			<li><a href="#">DROP DOWN 1</a></li>
			<li><a href="#">DROP DOWN 2</a></li>
			<li><a href="#">DROP DOWN 3</a></li>
		</ul>
	</li>
</ul>
</div>

</body>
</html>

solved it by removing a few <li> tags

also you can use the css sprite nav that uses the javascript sfhover function, google and youll see it.

.leftnav {
	padding-top:244px;
	width:188px;
	padding-left:12px;
	color:#000000;
	font-family:Arial;
	font-weight:bold;
	float:left;
	clear:both;
}
.leftheading {
	background-image: url(../images/rightstyle.jpg);
	width:178px;
	height:30px;
	padding-top:5px;
	padding-left:10px;
	background-repeat:no-repeat;
	color:#FFFFFF;
	font-family:Arial;
	font-weight:bold;
	z-index:10;
}
ul.menu1, ul ul {
	float:left;
	clear:both;
	padding:0; 
	margin:0;
	bottom:20px;
	border:0; 
	list-style-type:none; 	
	overflow:hidden; 
	background:#ffe6a3; 
	width:178px; 
	text-align:left;
	font-size:10pt; 
	color:#000000; 
	border:0;
}
ul.menu1 table {
	border-collapse:collapse; 
	padding:0; margin:0; 
	font-size:1em;
}
ul.menu1 ul {
	margin-left:1em;
}
ul.menu1 li {
	text-indent:10px;
}
ul.menu1 li.drop {
	margin-bottom:-2px;
}
ul.menu1 li a,ul.menu1 li a:visited {
	display:block; 
	width:178px; 
	height:2em; 
	line-height:1.2em; 
	text-decoration:none;
	color:#000000;
}
ul.menu1 li a.last, 
ul.menu1 li a.last:visited {
	display:block; 
	width:178px;; 
	line-height:1.2em;
}
ul.menu1 li ul {
	display:none;
}
ul.menu1 li:hover a,ul.menu1 li a:hover {
	border:0; 
	color:#000000;
	font-weight:bold;
}
ul.menu1 li:hover ul, 
ul.menu1 li a:hover ul {
	display:block; 
	width:168px;; 
	margin-top:-1px;
}
ul.menu1 li:hover ul li a, 
ul.menu1 li a:hover ul li a {
 	background:#ffe6a3; 
	color:#a51f17;
	font-weight:bold;
}
ul.menu1 li:hover ul li:hover a, 
ul.menu1 li a:hover ul li a:hover {
	background:#ffe6a3;
	color:#000000;
}
.maincontent {
	float:left;
	position:absolute;
	top:244px;
	padding-left:215px;
	width:618px;
	font-family:Arial;
	font-weight:normal;
	font-size:10pt;
	clear:both;
}

Html -:

<div class="maincontent">
<p>test</p>
<p>test</p>
<p>test</p>
<p>test</p>
</div>
<div class="leftnav">
<div style="background-color:#ffe6a3;width:188px;min-height:600px;bottom:20px;">
<div class="leftheading">Participants</div>
<ul class="menu1">
<li class="drop"><a href="#">Growers<!--[if IE 7]><!--></a><!--<![endif]--><table><tr><td>
	<ul>
	<li><a href="#">Grower Profile</a></li>
	<li><a href="#">2</a></li>
	<li><a href="#">3</a></li>
	<li><a href="#">4</a></li>
	</ul>
	</td></tr></table><!--[if lte IE 6]></a><![endif]-->
</li>
<li class="drop"><a href="#">ColorStars<!--[if IE 7]><!--></a><!--<![endif]--><table><tr><td>
	<ul>
	<li><a href="#">1</a></li>
	<li><a href="#">2</a></li>
	<li><a href="#">3</a></li>
	<li><a href="#">4</a></li>
	</ul>
	</td></tr></table><!--[if lte IE 6]></a><![endif]-->
</li>
<li class="drop"><a href="#">Rules<!--[if IE 7]><!--></a><!--<![endif]--><table><tr><td>
	<ul>
	<li><a href="#">1</a></li>
	<li><a href="#">2</a></li>
	<li><a href="#">3</a></li>
	<li><a href="#">4</a></li>
	</ul>
	</td></tr></table><!--[if lte IE 6]></a><![endif]-->
</li>

<li class="drop"><a href="#">FAQs<!--[if IE 7]><!--></a><!--<![endif]--><table><tr><td>
	<ul>
	<li><a href="#">1</a></li>
	<li><a href="#">2</a></li>
	<li><a href="#">3</a></li>
	<li><a href="#">4</a></li>
	</ul>
	</td></tr></table>

</ul>
</div></div>

behavior: url("csshover3.htc");
it works.
thank you