Im helping a friend of mine make a site for chemistry class and Im having trouble getting it to work right in IE. The header and the nav bar on the side are out of place and I dont know how to fix it.

Site located here (http://www.ioc.clanservers.com/sean/test/)

and heres the css for it:

body
{ margin-top: 0;
margin-bottom: 0;
margin-left: 0;
margin-right: 0;
padding-left: 0;
padding-right: 0;
background-color: #88b238;
}

#header {
margin: 20px;
padding: 10px;
height: 100px;
margin-left: 115px;
background-image: url(marie.gif);
background-repeat: no-repeat;
}
#left {
position: absolute;
left: 15px;
top: 160px;
width: 200px;
}
#center {
top: 0;
margin-left: 270px;
margin-right: 15px;
padding: 10px;
border: 1px solid black;
background-color: #c2d98f;
}

#footer {
height: 10px;
padding: 5px;
}

h2{
font-family: Bodoni MT;
font-size: xx-large;
}

a:link {
color: black;
text-decoration:none;
}

a:visited {
color: black;
text-decoration:none;
}

a:active {
background-color: black;
text-decoration:none;
}

a:hover {
color: black;
text-decoration: underline;
}
</style>