Hi im new to this forum and im having a cross browser compatability issue with a simple menu i developed using CSS

The menu should display horizontally in all browsers but some versions of IE Fire Fox and

Here is the current code links edited for privacy

<HTML>
<ul id="menu">
<li><a href="#nogo" target="_self" title="Forum">Contact Us</a></li><li><a href="#nogo" target="_self" title="Forum">Key People</a></li>
<li><a href="#nogo" target="_self" title="Forum">Medical Equipment</a</li>
<li><a href="#nogo" target="_self" title="home">Services</a></li> </ul>

And here is the <CSS>

ul#menu{
margin-top:0px;
padding:0;
list-style-type:none;
width:900px;
position:relative;
display:block;
height:20px;
}

ul#menu li{
display:block;
float:right;
margin: 2px 2px 0;
pading:0;
border:0px;
}

ul#menu li a{
display:block;
float:right;
color:#a3a3a3;
text-decoration:none;
padding:5px 30px 5px 30px;
margin-right:-1px;
margin-top:-2px;
height:20px;
}

ul#menu li a:hover{
background:lightgrey;
}

I apologize for my code as im a sloppy developer bad habits die hard, also the formatting may be off as i have posted this via iPad

Any Insites would be greatly appreciated!