ti invio il link di una pagina qualunque, tanto il problema si ripropone ovunque in tutte e ti invio anche il codice del file css(menu.css) che dovrebbe contenere il css colpevole, non che il codice del file che produce l'elenco a tendina che deve apparire; eccoli di seguito:
http://www.new-soft.it/atelier982_servizi.asp
codice:
#azienda{
	visibility: hidden;
	position: absolute;
	position: absolute;
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #FFFFFF;
	margin: 0px;
	padding: 0px;
}
	
#azienda ul{
	border: none;
	margin: 0px;
	padding: 0px;
}
#azienda li{
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #ffffff;
	margin: 0px;
	padding: 0px;
	border-top: 1px none #666666;
	border-right: 1px solid #666666;
	border-bottom: 1px solid #666666;
	border-left: 1px solid #666666;
	width: 177px;
	display: block;
	height: 15px;
	background-color: #eaeaff;
}
#azienda li a:hover{
	background-color: #7879A8;
	margin: 0px;
	display: block;
	padding-right: 20px;
	padding-top: 0px;
	padding-bottom: 0px;
	padding-left: 0px;
	height: 15px;
	color: #FFFFFF;
}

#software{
	visibility: hidden;
	position: absolute;
	position: absolute;
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #FFFFFF;
	margin: 0px;
	padding: 0px;
}
	
#software ul{
	border: none;
	margin: 0px;
	padding: 0px;
}
#software li{
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #ffffff;
	margin: 0px;
	padding: 0px;
	border-top: 1px none #666666;
	border-right: 1px solid #666666;
	border-bottom: 1px solid #666666;
	border-left: 1px solid #666666;
	width: 177px;
	display: block;
	height: 15px;
	background-color: #EFF8F1;
}
#software li a:hover{
	background-color: #8DAF8C;
	margin: 0px;
	display: block;
	padding-right: 20px;
	padding-top: 0px;
	padding-bottom: 0px;
	padding-left: 0px;
	height: 15px;
	color: #FFFFFF;
}
#soluzioni{
	visibility: hidden;
	position: absolute;
	position: absolute;
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #FFFFFF;
	margin: 0px;
	padding: 0px;
}
	
#soluzioni ul{
	border: none;
	margin: 0px;
	padding: 0px;
}
#soluzioni li{
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #ffffff;
	margin: 0px;
	padding: 0px;
	border-top: 1px none #666666;
	border-right: 1px solid #666666;
	border-bottom: 1px solid #666666;
	border-left: 1px solid #666666;
	width: 177px;
	display: block;
	height: 15px;
	background-color: #F7F5EE;
}
#soluzioni li a:hover{
	background-color: #aeae8c;
	margin: 0px;
	display: block;
	padding-right: 20px;
	padding-top: 0px;
	padding-bottom: 0px;
	padding-left: 0px;
	height: 15px;
	color: #FFFFFF;
}
#web{
	visibility: hidden;
	position: absolute;
	position: absolute;
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #FFFFFF;
	margin: 0px;
	padding: 0px;
}
	
#web ul{
	border: none;
	margin: 0px;
	padding: 0px;
}
#web li{
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #ffffff;
	margin: 0px;
	padding: 0px;
	border-top: 1px none #666666;
	border-right: 1px solid #666666;
	border-bottom: 1px solid #666666;
	border-left: 1px solid #666666;
	width: 177px;
	display: block;
	height: 15px;
	background-color: #F7EEF1;
}
#web li a:hover{
	background-color: #AE8C8C;
	margin: 0px;
	display: block;
	padding-right: 20px;
	padding-top: 0px;
	padding-bottom: 0px;
	padding-left: 0px;
	height: 15px;
	color: #FFFFFF;
}

#index{
	visibility: hidden;
	position: absolute;
	position: absolute;
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #FFFFFF;
	margin: 0px;
	padding: 0px;
}
	
#index ul{
	border: none;
	margin: 0px;
	padding: 0px;
}
#index li{
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #ffffff;
	margin: 0px;
	padding: 0px;
	border-top: 1px none #666666;
	border-right: 1px solid #666666;
	border-bottom: 1px solid #666666;
	border-left: 1px solid #666666;
	width: 80px;
	display: block;
	height: 15px;
	background-color: #E8E8E8;
	text-align: left;
}
#index li a:hover{
	background-color: #999999;
	margin: 0px;
	display: block;
	padding-right: 0px;
	padding-top: 0px;
	padding-bottom: 0px;
	padding-left: 0px;
	height: 15px;
	color: #FFFFFF;
}
codice:
<div id="index">
  <ul>[*]<a href="profilo.asp" onmouseover="clearTimeout(tim);swap1(this)" onmouseout="waitAndClear(activeLayer);swap2(this)">
    Azienda</a>[*]<a href="prodotti.asp" onmouseover="clearTimeout(tim);swap1(this)" onmouseout="waitAndClear(activeLayer);swap2(this)">
    Prodotti</a>[*]<a href="soluzioni.asp" onmouseover="clearTimeout(tim);swap1(this)" onmouseout="waitAndClear(activeLayer);swap2(this)">
    Soluzioni</a>[*]<a href="web.asp" onmouseover="clearTimeout(tim);swap1(this)" onmouseout="waitAndClear(activeLayer);swap2(this)">
    Web</a>[/list]
</div>
spero che questo possa essere sufficiente