HTML layout fix

I have a small problem with my site's layout. I use a couple of html tables in each page to keep the site layout held in place nicely, however due to slight differences in pages, the site's design appears to shift slightly if you view a different page. I need all the pages to have the tables lined up so the design is constant throughout the site. This needs to work for both IE and firefox. It doesn't matter if the site's design appears slightly differently in firefox to IE. But as long as the site's design is constant when you look at all the pages on that browser. Hope that makes sense. There are 8 pages that need re-aligning. But it's all the same design. Sorry for the somewhat ambiguous explanation, but it is actually quite a simple project and it shouldn't take long at all for an experienced web designer, who knows a little php (because the pages pull in php includes to complete the design). Therefore, I'm not looking to pay too much for this. I'll send you screenshots of the problem if you request them. But it's exactly the same design on all 8 pages. It has just got slightly miss-aligned because I added some content to the page.