The problem is that you are using the table cells as a whole and as a result everything you add in the middle cell moves the left and right cells down also.This should get you out of that problem:
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><style type="text/css">/*Controls default text colors*/html, body { color: black;}/*Controls Header Cell*/.header { text-align: center;}/*Controls the left "table"*/.boxes { padding: 10px; border: 1px solid black; background-color: #5E5E5E; width: 100%;}/*Controls right "table"*/.imagebox { border: 0px; padding: 10px; background-color: #5E5E5E; width: 100%;}/*Controls the middle "table"*/.content { vertical-align: top; padding: 10px; border: 1px solid black; background-color: #5E5E5E;}/*Controls Left and Right Cells*/.cellwidth { width: 120px; vertical-align: top;}/*Controls the middle "Cell"*/.contentwidth { veritcal-align: top;}a:link { text-decoration: underline; color: #ffffff; font-weight:bolder;}a:visited { text-decoration: underline; color: #ffffff; font-weight:bolder;}a:hover { text-decoration: underline; color: #999999;}a:active { text-decoration: underline; color: #999999; font-weight:bolder;}</style> </head><body><table> <tr> <td class="header" colspan="3"> Header Image </td> </tr> <tr colspan="3"> <td class="cellwidth"> <table class="boxes"> <tr> <td> <p><a href="#">Link 1</a></p> <p><a href="#">Link 2</a></p> <p><a href="#">Link 3</a></p> <p><a href="#">Link 4</a></p> <p><a href="#">Link 5</a></p> <p><a href="#">Link 6</a></p> <p><a href="#">Link 7</a></p> </td> </tr> </table> </td> <td class="contentwidth"> <table class="content"> <tr> <td> <p align="justify">Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec id sem ut libero scelerisque dictum. Suspendisse molestie venenatis turpis. In pellentesque. Vivamus suscipit. Fusce at justo in sem tristique tempor. Mauris sit amet metus. Fusce accumsan metus eget quam. Mauris dapibus dictum justo. Mauris neque metus, sodales ut, luctus non, ullamcorper eu, ante. Nulla pede. Ut tincidunt facilisis est. Ut cursus dignissim orci. </p> <p align="justify">O fortuna, velut luna statu variabilis, semper crescis aut descrescis; vita detestabilis nunc obdurat et tunc curatludo mentis aciem, egestatem, potestatem dissolvit ut glaciem. </p> <p align="justify">Nunc tellus erat, venenatis sit amet, malesuada luctus, cursus sit amet, erat. Suspendisse tortor ligula, facilisis id, molestie facilisis, consectetuer sit amet, erat. Nunc quis quam a turpis volutpat consectetuer. Praesent quis ipsum. Cras risus. Pellentesque mauris nulla, lacinia id, laoreet non, gravida at, lorem. Aliquam egestas. Curabitur vel nibh. Fusce ut dolor. Curabitur imperdiet mollis nunc. Donec tellus diam, sollicitudin eu, mollis semper, condimentum vitae, velit. Quisque ut lacus in lectus sodales fringilla. Integer eu purus. Aliquam mauris sem, porta at, dignissim non, aliquam ac, lectus. Etiam id lorem. Integer sed nisi. Aenean ut ligula.</p> </td> </tr> </table> </td> <td class="cellwidth"> <table class="imagebox"> <tr> <td> <img src="" alt="" style="height:80px; width:60px;"><br> <img src="" alt="" style="height:80px; width:60px;"> </td> </tr> </table> </td> </tr></table></body></html>