I know this is a common issue and usually I can find a work around. However in this situation, the error occured spontaneously and in fact, it still displays properly in IE but just as a flash, which then disappears. It worked well in IE up until last night when I changed the add to cart button and removed the text 'Product image' from the index.php english file.
This link is an excellent example. The box at the top displays properly, using essentially the same styling as the product listings. In IE the product backgrounds and borders now dissappear.
Using IE 8.