website header hiding behind content when position is fixed

I am designing a website for a school and I want the header of site to be fixed just like facebook has. I tried the fix provided by [this][1] question on stackoverflow but it was hardly of any use in the header. I have an image, basically the logo of the school, where I do position: fixed, but the header hides behind the page.

HTML:

<body>
  <div id="header" > <img src="images/iesheader_nnew1.jpg" /></div>
    
    <div id="menu">
      <ul>
           <li><a href="index.html"><abbr title="Home">Home&nbsp;&nbsp;</abbr></a></li>
           <li><a href="aboutus.html"> <abbr title="About Us">About Us&nbsp;&nbsp;</abbr> </a></li>
           <li><a href="acad.html"><abbr title="Academics">Academics</abbr></a></li>
           <li><a href="admin.html"><abbr title="Administration">Administration</abbr></a></li>
           <li><a href="news.html"><abbr title="News">News</abbr></a></li>
           <li><a href="contact.html"><abbr title="Contact Us">Contact Us</abbr> </a></li>
           <li><a href="photo.html"><abbr title="Photo Gallery">Photo Gallery</abbr> </a></li>
      </ul>     
        <div class="cleaner"></div>
</div>

CSS:

#header {
    margin-left: 0px;
    width: auto;
    height: 90px;
    padding: 0px;
    padding-left:185px;
    font-size: 35px; color:#FFFFFF; 
    background-color: #f6c491;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
}
#menu {
    position: relative;
    clear: both;
    width: auto;
    height: 38px;
    padding: 0;
    padding-left:185px;
    background-color:#FFFFFF;   
    margin-bottom: 10px;
    margin-left:0px;
}

#menu ul {
    float: left;
    width: 960px;
    margin: 0;
    padding: 0;
    list-style: none;
}

#menu ul li {
    padding: 0px;
    margin: 0px;
    display: inline;
}

#menu a {
    float: left;
    display: block;
    padding: 8px 20px;
    font-size: 14px;
    font-weight: bold;
    text-align: center;
    text-decoration: none;
    color: #000;
    outline: none;
    border: none;   
    border-top: 3px solid black;
}

I tried a number of solutions to that, but whatever I do, the header goes behind the page. I want the menu bar also to be fixed but it also is the same... [1]: Page navigation with fixed header

Solution

Add z-index:1000 to the #header css, and add padding-top to the body css which should be a bit more than header's height. For example, if the header's height is 40px, put the padding-top: 50px to the body css and it should work.