[Dismounted]

Originally Posted by JakeS

Well googling, tells me all this is to do is so the computer can read it?!

Kind of. Semantic HTML is the creation of HTML documents with the author's intended meaning (and a tag's intended meaning). The famous example is the use of tables for positioning. Tables are for tabular data, not to position things. Another is <i> and <em>. A by-product of this is the fact that spiders can "read" a site better.

Again, semantic HTML is not replacing all tables with divs. I can see in your code there are just random nested containers. An example is this:

<div>    
    <div class="tcat"><strong>&raquo;Screenshots</strong></div>
</div>
<div>
    <div class="menuboxmiddle">Gallary</div>
</div>

A menu is a list of links, and therefore should use a <ul> (unordered list) element. That's the kind of stuff semantic HTML intends to be.

Originally Posted by JakeS

Main content box has a margin.. and is still there, BUT. It's now got a frigging white border in place of a margin were it never used to, but had the margin matching the colour needed. Is there a way to fix that?

Screenshot example please? Don't really understand the problem.

Originally Posted by JakeS

And now, I used to have 2 tables next to each other, one on the left, one on the right.. now it sits under it now it's a div!

Have you tried floating the containers?