.Menu
{
    list-style-type: none;
    margin-top: 30px;
}
.Menu li
{
    display: inline;
    margin-left: 35px;
}
.Menu li a
{
    font-family: Arial;
    font-weight: bold;
    font-size: 18px;
    color: #7a8090;
    text-decoration: none;
    width: 82px;
    height: 37px;
    float: left;
    margin-left: 25px;
}
.Menu li a:hover
{
    background-image: url(/_Media/Images/menuhover.png);
    color: #FFFFFF;
    width: 82px;
    height: 37px;
    background-position: center right;
}

<ul class="Menu">
                            <li><a href="#">Home</a></li><li><a href="#">About</a></li><li><a href="#">Portfolio</a></li><li>
                                <a href="#">Blog</a></li><li><a href="#">Contact</a></li></ul>