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?

Thanks!
Bryan