Hi,
As KLB said you have a lot of errors in there 
There is no such thing as negative padding or #silver ! You have used that quite a few times. You have also missed out the hyphen in a lot of places.
Heres your code tidied up and added a full doctype added and some box model hacks fixed. However now that its fixed it may not look the way you want. I've fixed the left nav that was in the middle of the page in ie5.
Code:
/* CSS Document */
/* The text-align: center; is used to prevent the following browsers from not centering the containing blocks: * NN4 (Mac and Win) * Win/IE4 * Win/IE5 * Win/IE5.5 * Win/IE6 (when in quirks-mode) using this will only take effect in those browser, the CSS code will overall it in browsers tha support the code */
body { text-align: center;
background-color: #EBEBEB; }
/* Entire Page (Container) */
#container {
background-image: url(http://www.wizsyst.com/wiz/Assets/jpgs/bg_6.jpg);
background-repeat: no-repeat;
background-position: bottom right;
background-color: #fff;
width: 759px;
margin-left: auto;
margin-right: auto;
text-align: left;
color: #333;
border: 1px solid gray;
line-height: 130%;
}
* html #container {width:761px;w\idth:759px}
/* Heading (Cabe?alho) */
#top {
background: #fff url(http://www.wizsyst.com/wiz/Assets/top_2.gif) no-repeat right top;
height:90px;
border-bottom: 1px solid gray;
position:relative;
}
/* Exemplo de "Descendant Selector" */
#top h1 {
padding: 0;
margin: 0; }
/* Flah utilizado no topo da p?gina */
#flash_topo {
margin-top:-0.4em;
float: left; }
/* Leftnav (Navega??o da Esquerda */
#leftnav {
float: left;
width: 160px;
margin: 0;
margin-left: 3px;
padding: 10px;
}
* html #leftnav { display:inline;width:180px;w\idth:160px}
/* Links - Navega??o Esquerda */
#leftnav a { text-decoration: none; }
#leftnav a:hover { color: red;
text-decoration: underline;
width: 100%; }
/* Rightnav (Navega??o da Direita) */
/* Content (Corpo - Coluna Principal) */
/* The max-width: 36em, sets the maximum width on the main content. Although IE browsers will ignore the rule, the other standard compliant browsers will not alow the content area to go wider than the width you specify. */
#content {
font-family: Helvetica, sans-serif;
font-size: 12px;
color: #000;
margin-left: 210px;
margin-right: 0px;
padding-top: 0;
border-left: 1px solid gray;
}
/* commented backslash hack \*/
* html #content {height:1%}
/* end hack */
#content h1 { font-family: Helvetica, sans-serif;
font-size: 17px;
border: 1px solid gray;
border-left: none;
border-right: none;
background-color: #DDDDDD;
}
#img1 img { padding-top: 0;
margin-right: -50em; }
#content h4 { font-size: 14px;
color: green;
border-bottom: 1px solid black;
}
#content h2 { font-size: 16px;
color: #999;
padding-bottom: 0;
margin-bottom: 0; }
#content a { font-size: 11px; }
#content a:hover { font-size: 11px;
color: green;
border: 1px solid silver;
background-color: #F8F8F8;
width: auto; }
#content p { margin-left: 4px; }
/* Alinhamento das imagens da p?gina Principal. */
#img2 img { float: left;
margin-left: 0;
padding-left: 0;
}
#img2 { float: left;
}
#img3 { float: right;
margin-left: 10px;
padding-left: 10px;
margin-top: -3.5em;
}
/* Footer (Rodap?) */
/* The clear: both; command will force the footer below any floated elements above. */
#footer {
background: #ddd url(http://www.wizsyst.com/wiz/Assets/jpgs/rodape.jpg) no-repeat right bottom;
clear: both;
margin: 0;
padding: .5em;
color: #333;
border-top: 1px solid gray;
border-bottom: 1px solid gray;
padding-top: 2.2em;
margin-top: 2.2em; }
/* To remove the space above content in the "lefnav", "rightnav" and "content" */
#leftnav p { margin: 0 0 10px 0; }
#content h2 { margin: 0 0 .5em 0; }
/* Este id serve para alinha os campos de preenchimento de acordo com o gr?fico, assim como customizar os campos */
#campo1 input {
font-family: Tahoma, Arial, sans-serif;
color: #000;
background-color: #fff;
border: 1px solid gray;
font-size: 10px;
}
#campo1 {
font-family: Tahoma, Arial, sans-serif;
font-size: 11px;
color: #000;
position:absolute;
top:56px;
left:395px;
width:433px;
}
* html #campo1 {top:58px;left:396px;}
/* Bordas Navega??o Esquerda */
div.Article {
background: url(http://www.wizsyst.com/wiz/Assets/bo...cao/e_topo.gif) top left no-repeat;
width: 180px;
}
div.Article h2 {
background: url(http://www.wizsyst.com/wiz/Assets/bo...cao/d_topo.gif) top right no-repeat;
font-family: Helvetica;
font-size: 14px;
padding: 22px;
margin: 0;
padding-bottom: 1.2em;
padding-top: 10px;
}
div.ArticleBody {
background:url(http://www.wizsyst.com/wiz/Assets/bo...o/d_borda1.gif) top right repeat-y;
margin: 0;
margin-top: 0;
padding-left: 14px;
padding-top: 0px;
}
div.ArticleBody ul {
font-family: Helvetica, sans-serif;
font-size: 12px;
margin-left: 0;
padding-left: 0;
}
div.ArticleBody li { list-style: none;
padding-left: 14px;
background-image: url(http://www.wizsyst.com/wiz/Assets/lista/type_10.gif);
background-repeat: no-repeat;
background-position: 0.1em;
}
div.ArticleFooter {
background: url(http://www.wizsyst.com/wiz/Assets/bo...ao/e_fundo.gif) bottom left no-repeat;
}
div.ArticleFooter p {
background: url(http://www.wizsyst.com/wiz/Assets/bo...o/d_fundo2.gif) bottom right no-repeat;
display: block;
padding: 30px;
margin-top: 45px;
}
/* Comando Universal de margens */
* { margin: 0; padding: 0; }
/* Quem Somos */
#publico { font-size: 13px;
border: 1px solid gray;
border-right: none;
border-left: none;
background: silver;
width: auto;
}
#privado { font-size: 13px;
border: 1px solid gray;
border-right: none;
border-left: none;
background: silver;
width: auto;
}
#privado img { padding-top: 0;
margin-top: 3.5em; }
#business { font-size: 13px;
border: 1px solid gray;
border-right: none;
border-left: none;
background:silver;
width: auto;
}
/* Diferencial */
#instalacoes img { margin-left: 22px;
border: 4px double silver;
white-space: nowrap; }
/* Qualidade */
#textoInovacao1 { margin-right: 365px;
border: 1px solid gray;
border-top: none;
border-left: none;
background-color: silver; }
#textoInovacao2 { margin-right: 182px;
margin-left: 184px;
margin-top: -4.1em;
border: 1px solid gray;
border-top: none;
background-color: silver; }
#textoInovacao3 { margin-left: 367px;
margin-top: -4.2em;
border: 1px solid gray;
border-right: none;
background-color: silver; }
#textoJgrade { margin-left: 290px;
margin-top: -9.2em;
border: 1px solid gray;
border-top: none;
border-left: none;
border-right: none;
}
#textoSigem {
margin-left: 290px;
margin-top: -10.4em;
border: 1px solid gray;
border-top: none;
border-left: none;
border-right: none; }
#textoBusiness {
margin-left: 290px;
margin-top: -9em;
border: 1px solid gray;
border-top: none;
border-left: none;
border-right: none; }
/* Bordas - Not?cias */
div.News {
background: url(http://www.wizsyst.com/wiz/Assets/bo...ias/e_topo.gif) top left no-repeat;
width: 450px;
margin-left: 35px; }
div.News img { float: right; }
div.News h5 { background: url(http://www.wizsyst.com/wiz/Assets/bo...ias/d_topo.gif) top right no-repeat;
font-family: Helvetica, sans-serif;
font-size: 16px;;
padding: 22px;
margin: 0;
padding-bottom: 1.2em;
padding-top: 10px; }
div.News h6 { font-family: Helvetica, sans-serif;
font-size: 11px;
border-bottom: 1px solid olive;
width: 97%; }
div.NewsBody { background: url(http://www.wizsyst.com/wiz/Assets/bo...s/d_borda1.gif) top right repeat-y;
margin: 0;
margin-top: 0;
padding-left: 14px;
padding-top: 0px; }
div.NewsFoot { background: url(http://www.wizsyst.com/wiz/Assets/bo...s/e_fundo1.gif) bottom left no-repeat; }
div.NewsFoot p { background: url(http://www.wizsyst.com/wiz/Assets/bo...s/d_fundo1.gif) bottom right no-repeat;
display: block;
padding: 30px;
margin-top: 16px; }
Hope that helps.
Paul
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