Your page is way invalid (not coded to standards). This version is not much better as far as that goes, but looks the same in IE 7, Firefox 3, and Opera 10:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML>
<head>
<title>Example Website</title>
<link rel="stylesheet" href="/style/mystyle.css">
<style type="text/css">
body {
background-image: url("http://i49.tinypic.com/1fvmlh.png");
background-position: center;
background-repeat: repeat;
background-color: #C0C0C0;
background-attachment:fixed;
}
.main {
background-color:#fff;
}
</style>
</head>
<BODY>
<center>
<TABLE BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="976" HEIGHT="278">
<TR>
<TD ROWSPAN="1" COLSPAN="7" WIDTH="976" HEIGHT="194">
<IMG NAME="banner0" SRC="/layout/banner_1x1.png" WIDTH="976" HEIGHT="194" BORDER="0"></TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1" WIDTH="472" HEIGHT="25">
<IMG NAME="banner1" SRC="/layout/banner_2x1.png" WIDTH="472" HEIGHT="25" BORDER="0"></TD>
<TD ROWSPAN="1" COLSPAN="1" WIDTH="65" HEIGHT="25">
<a href="/index.htm"><IMG NAME="banner2" SRC="/layout/banner_2x2.png" WIDTH="65" HEIGHT="25" BORDER="0" onmouseover = "var old = this.src; this.src = '/images/home.png';"
onmouseout = "this.src = '/layout/banner_2x2.png';"></a></TD>
<TD ROWSPAN="1" COLSPAN="1" WIDTH="67" HEIGHT="25">
<a href="/about.html"><IMG NAME="banner3" SRC="/layout/banner_2x3.png" WIDTH="67" HEIGHT="25" BORDER="0" onmouseover = "var old = this.src; this.src = '/images/about.png';"
onmouseout = "this.src = '/layout/banner_2x3.png';"></a></TD>
<TD ROWSPAN="1" COLSPAN="1" WIDTH="108" HEIGHT="25">
<a href="/collection.html"><IMG NAME="banner4" SRC="/layout/banner_2x4.png" WIDTH="108" HEIGHT="25" BORDER="0" onmouseover = "var old = this.src; this.src = '/images/collection.png';"
onmouseout = "this.src = '/layout/banner_2x4.png';"></a></TD>
<TD ROWSPAN="1" COLSPAN="1" WIDTH="103" HEIGHT="25">
<a href="/available.html"><IMG NAME="banner5" SRC="/layout/banner_2x5.png" WIDTH="103" HEIGHT="25" BORDER="0" onmouseover = "var old = this.src; this.src = '/images/available.png';"
onmouseout = "this.src = '/layout/banner_2x5.png';"></a></TD>
<TD ROWSPAN="1" COLSPAN="1" WIDTH="74" HEIGHT="25">
<a href="/terms.html"><IMG NAME="banner6" SRC="/layout/banner_2x6.png" WIDTH="74" HEIGHT="25" BORDER="0" onmouseover = "var old = this.src; this.src = '/images/terms.png';"
onmouseout = "this.src = '/layout/banner_2x6.png';"></a></TD>
<TD ROWSPAN="1" COLSPAN="1" WIDTH="87" HEIGHT="25">
<a href="/contact.html"><IMG NAME="banner7" SRC="/layout/banner_2x7.png" WIDTH="87" HEIGHT="25" BORDER="0" onmouseover = "var old = this.src; this.src = '/images/contact.png';"
onmouseout = "this.src = '/layout/banner_2x7.png';"></a></TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="4" WIDTH="712" HEIGHT="59">
<IMG NAME="banner8" SRC="/layout/banner_3x1.png" WIDTH="712" HEIGHT="59" BORDER="0"></TD>
<TD ROWSPAN="1" COLSPAN="3" WIDTH="264" HEIGHT="59">
<IMG NAME="banner9" SRC="/layout/banner_3x2.png" WIDTH="264" HEIGHT="59" BORDER="0"></TD>
</TR>
</TABLE>
<table width="902" height="500" border="0" cellspacing="1" cellpadding="2" class="main"><tr><td bgcolor="#ffffff" valign="top">
<td class="main2" valign="top" width="50%" height="100%">
<IFRAME name="home" src="/edit/home.html" style="border:none" frameborder="0" width=100% height=100% marginwidth=0 marginheight=0 scrolling=auto></IFRAME>
</td>
<td class="main2" valign="top" width="10%"></td>
<td class="main2" valign="top" width="35%" height="100%">
<br>
<br>
<br>
<IFRAME name="updates" src="updates.html" style="border:none" frameborder="0" width=239 height=277 marginwidth=0 marginheight=0 scrolling=auto></IFRAME>
<p>
<img src="/images/pewter.png">
</td>
</tr></td></table>
<center><font size="1">
Layout © <a href="mailto:x00petlover00x@hotmail.com?subject=Website Design Inquiry"><font color="000000">Nicole Lyons</font></a>
<br>
Animal Images © Aaron Jones - Used with permission
</font></center>
</body>
</html>