I'm not going to delve too deep here, but here are a couple of tips:
When you give something a width, specify the measurement. If you want it to be in pixels, type width="910px". This might help a bit.
You should have a look into using css for your layouts rather than tables and presentation html. Trust me: your code will be easier to deal with if you do.
Now, if I were to want to center something, and make sure that it stayed the same width as the page resized, here is a simple version of what I'd do.
HTML:
Code:
<div id="wrapper">
<div id="content">
<p>Content goes here</p>
</div>
</div>
And then, in my css file:
Code:
#wrapper{margin-left: auto; margin-right: auto; width:910px; background-color:teal;}
The automatic left and right margins center it on the page, and I've just put the color and width in so you can see it were you to preview it.
I hope all this helps,
Ellyn