Problem is often caused by Google Chrome being uninstalled. Fixed it by following the final step listed at http://support.microsoft.com/kb/310049
Verify that the String (Default) value of the “HKEY_CLASSES_ROOT \.html” key is “htmlfile”
- Click Start, and then click Run.
- In the Open box, type regedit, and then click OK.
- Locate, and then click the following registry subkey:
- Make sure that the value of the String (Default) is “htmlfile”. If it’s not “htmlfile”, right-click (Default), click Modify, input htmlfile in the Value data box, and then click OK. See image.
- Exit Registry Editor.