#nav ul li.software a {
display:block;
width:77px;
height:21px;
color:#000;
text-decoration:none;
background:url('images/selected_tab.gif') no-repeat;
}

#nav ul li.software a:hover { 
display:block;
width:77px;
height:21px;
color:#000;
text-decoration:none;
background:url('images/selected_tab.gif') no-repeat;
}