I hate questions that start with "all the sudden this happened."
I was using Dreamweaver CS5.5 along with some other things I had open. I was off doing something with one of the other things and came back to Dreamweaver. It was in design view not live view. All it shows me the HTML without merging the CSS that goes with it. However, when I hit Live View, it merges the code and displays just fine.
My machines been acting funny lately. Earlier today, Outlook kept shutting down, but that stopped. Some times my cursor moves strangely. Surely, this isn't a virus causing this with Dreamweaver. I run good protection and keep it updated.
I thought maybe IIS was not running, but it is. Without it, it probably would not have merged the CSS in live view. What could I possibly have done to this thing?
You may also want to check your code against the validator at http://validator.w3.org
DW's Design View is much more sensitive to code errors than Live View or an actual browser. Relatively simple errors will make Design View go crazy while Live View and browsers will ignore them.
Thanks everybody, I did both of your suggestions to no avail. I looked and looked and couldn't find a reason for it. I had a backup of the files from a few days ago and I started replacing individual files to find the problem, but that got old. So I finally just copied in the whole backup and it's fine.
This had to be something creepy we'll never track down - not worth the time.
Thanks for trying.