Exactly what did the "updates" consist of? A complete redesign, or change of elements on a page?

Regardless, something like that shouldn't cause DW to behave in that way.

What happens if you click the "Split View" button? Anything? Nothing?

Can you still open the old pages in "Split View"?

So is the button gone?

What happens when you look at it in Design view? Blank page?

This sounds weird and as suggested above shouldn't break design view more then it already is out of the box.

The buttons are still there for split view and design view but all that displays is a big empty box with the background color. The code-view and the code part of the split-view both look fine.

We had them change the header from an image to HTML, added a slide show on most of the pages. Somewhere along the way we lost the ability to see anything in split or design view.

The backup copies are all the new pages so we really can't remember the old pages other than the fact that we could see them.

Any help on ideas is appreciated. I've checked adobe and the ww search.

If you are seeing the background colour for your site, then the Design View is working.

An initial reaction to what you describe would be that they are possibly doing something funky with dhtml (slideshows). Some slideshows (and menus) will slide in divs from negative positions, so that you don't see anything initially.

On your design view can you see any square outlines or little yellow boxes with designs on them (for example, exclamation marks, anchors or letters)?

They have definitely not changed your page structure to use frames or includes?

Is the code that you want to edit between script / noscript tags?