add this code into your style.css
Code:
.bold_bg {
background: transparent url(../images/your_image.jpg);
background-repeat: repeat-x;
background-color:#000000;
font-weight: bold;
}
and replace the class="bold" into class="bold_bg"
Code:
<td>Sign Up</td>
<td style="padding-right: 5px; padding-left: 5px; padding-bottom: 0px; padding-top: 0px">|</td>
<td>Log In</td>
ok