I forwarded same question to support and was informed that the preview file association had been changed. To re-associate the file back to your browser it was suggested to do the following:

1. close all programs
2. open windows explorer and open "Tools/Folder options.."
3. when "folder option" window opens, click on Folder Types
4. scroll down the "Registered File Types" using down arrow key on key board till you get to the "HTML" extension
5. remove (delete) this extension
6. click the "ok" button on the Folder options window after you have removed this file type
7. Run IE or whatever browser your using and see if it recreates the file type association.

I'm using Firefox and instead of deleting or removing it, I had the option of restoring it. I did it that way and AW2k is back to working.