Microsoft Visual Web Developer 2010 Express “class not registered” error when trying to open a CSS file

Question

Visual Studio gives me the following error message when opening a CSS file:

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Microsoft Visual Web Developer 2010 Express
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Class not registered.
Looking for object with CLSID: {D9B3211D-E57F-4426-AAEF-30A806ADD397}.
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OK   
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Opening and editing HTML and JS files work fine. I found a few suggestions via google saying that reinstalling fixed it. I spent a few hours uninstalling VWD and its pre-requisites and reinstalling it only to get the same error. Does anyone have any insight?

Update: attempting to open a CSS file inside a solution gives me a different error message:

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Microsoft Visual Web Developer 2010 Express
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The operation could not be completed. Unspecified error 
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OK   
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Answer 1

The new error message led me to this question: CSS file not opening in Visual Studio 2010 SP1?

The specific fix for these messages (for me, at least) is to manually download and reinstall Web Standards Update for Microsoft Visual Studio 2010 SP1.