Remember that the cells <td></td> are placed inside the rows <tr></tr> and rows are placed inside the table
<table></table>.
<html>
<head>
<title>Computer Books</title>
</head>
<body>
<caption>IT Learning</caption>
<table>
<tr bgcolor="#ff0000">
<th></th>
</tr>
<tr>
<th align="center" width="200px">BOOKS</th>
<th align="center" width="200px">SOFTWARE</th>
<th align="center" width="200px">HARDWARE</th>
</tr>
<tr>
<th align="center" >Creative Design</th>
<th align="center" >Adobe</th>
<th align="center" >Asus Notebook</th>
</tr>
<tr>
<th align="center" >Office Productivity</th>
<th align="center" >Microsoft</th>
<th align="center" >inFocus Projector</th>
</tr>
</table>
</body>
</html>