Add to cart box going behind right side box’s

Hi all I have a bit of a bug on my site where on some of my products the add to cart box will go behind the right side box bar.

If its viewed in a small browser window its ok but if you stretch it bigger the move to the right the box moves until it is behind the side box’s. What is confusing me is that it is not all of my products it is just some of them. This is one of the problem products http://www.aquacooledpc.co.uk/index.php?main_page=product_info&products_id=344

Anyone out there have clues that can help?
Thanks

#cartAdd declarations appear in both:

stylesheet.css
and
product_info.css

Decide on what you want to happen with #cartAdd

and consolidate the declarations so that there's no confusion.

(I have not looked specifically, but there may be other duplications in the stylesheets. You should consolidate where possible).

Thanks for that i made them changes but its still not working.

By the way I forgot to point out that the bug is only with IExplorer it is fine in Firefox. :frusty: