Starcraft 2, WoW, and Diablo 3.
This problem started on Tuesday (right after the patch). I've tried many "fixes" that have been rumored to work but none of them have worked.
1. Make sure that Windows is set to show hidden files.
Here's how to do that: http://windows.microsoft.com/en-US/windows-vista/Show-hidden-files
2. Navigate to the C:\ProgramData folder and delete the Battle.net and Blizzard Entertainment folders.
3. Launch WoW.
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