td 넓이를 400으로 주었는데요.
게시만은 400사이즈 맞는데 뒤에 힌 공백부분이 남네요.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>무제 문서</title>
</head>

<body bgcolor="#000000">
<table border="1" align="center">
<tr>
<td width="400" bgcolor="#FFFFFF" align="center">

----게시판----

</td>
</tr>
</table>
</body>
</html>