Blank Icon Shown for HTML Files

Running Vista 64 Ultimate. After installing Office 2007, all of my *.htm, *.html and *.mht files are now shown in Explorer as the blank white icon. I confirmed that the Default Icon settings under HKEY_CLASSES_ROOT match those of another Vista machine, yet something is preventing Explore from displaying the appropriate icons for the aforementioned file types.

I could just force the file types to reference the correct icons within the Internet Explorer executable, but I would rather get to the cause of the situation, and leave the registry settings at there default value of "%1", just like my other Vista machine.

Any clues on how to remedy this behavior?