Instead of putting style="height:auto" can we try having height attribute for Table table1 to 100%.
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<style type="text/css">
html, body {
height: 100%;
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<table height=100% width=100% border=1 cellpadding=0 cellspacing=0>
<tr><td colspan=2 height=40px></td></tr>
<tr><td width=75% id="cell1">
<table height=100% width=100% bgcolor=red id="table1"><tr><td></td></tr></table>
</td>
<td></td>
</tr>
</table>
</body>
</html>
Hope this helps !!