Cita:
Iniciado por alexg88 
¿Puedes poner el esqueleto HTML de la página?.
Para darnos una idea.
asi es ek html:
<html>
<head>
<title>Ejemplo de tres columnas con CSS</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link type="text/css" href="index5.css" rel="stylesheet" />
<script src="Scripts/AC_RunActiveContent.js" type="text/javascript"></script>
</head>
<body>
<!--************************************************** ************************************************** ***********************-->
<!-- CABECERA -->
<!--************************************************** ************************************************** ***********************-->
<div id="contenedor_cabecera">
<div id="col_der2">
<img src="Imagenes/fondonegro.gif" height="240px">
</div>
<div id="col_izq2">
<img src="Imagenes/fondorojo.gif" height="240px">
</div>
<div id="col_cen2">
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0" width="530" height="250">
<param name="movie" value="animacion/cabezera.swf">
<param name="quality" value="high">
<param name="wmode" value="transparent"/>
<embed src="animacion/cabezera.swf" wmode="transparent" quality="high" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash" width="530" height="250"></embed>
</object>
</div>
</div>
<!--************************************************** ************************************************** ***********************-->
<!-- CONTENIDO -->
<!--************************************************** ************************************************** ***********************-->
<div id="contenedor">
<div id="col_der1"></div>
<div id="col_izq1">
</div>
<div id="col_cen1">
<p>prueba</p>
</div>
</div>
<!--************************************************** ************************************************** ***********************-->
<!-- PIE -->
<!--************************************************** ************************************************** ***********************-->
<div id="pie">
<div id="col_cen3">
<img src="Imagenes/pie.gif" width="1024" />
</div>
</div>
</body>
</html>
y asi el css
#contenedor {height: 200px;margin:0; margin-left:171px; width:1024px;}
#col_der1 {float: right; width: 240px;background-color: #000000;height: 100%;}
#col_izq1{float: left; width: 240px;background-color: #F02137;height: 100%;}
#col_cen1 {background-color: #FFFFFF;height: 100%;}
#contenedor_cabecera {height: 200px;margin:0; margin-left:171px; width:1024px;}
#col_der2 {float: right; width: 240px;background-color: #000000;height: 100%;}
#col_izq2 {float: left; width: 240px;background-color: #F02137;height: 100%;}
#col_cen2 {background-color: #FFFFFF;height: 100%;}
#pie {height: 200px;margin:0; margin-left:171px; width:1024px; }
#col_der, #col_izq, #col_cen {height: 100%;}
#col_der3 {float: right; width: 240px;height: 100%;}
#col_izq3 {float: left; width: 240px;height: 100%;}
#col_cen3 {background-color: #FFFFFF;height: 100%;}
#pie
{
float:none;
clear:both;
margin-left:171px;
}