Just this afternoon all my icons in Windows started to display incorrectly. So I would click on the Visual Studio icon and Notepad++ would start up. It turns out this is very easy to fix. SImply create a batch file and copy the following into it
taskkill /F /IM explorer.exe cd /d %userprofile%AppDataLocal attrib –h IconCache.db del IconCache.db start explorer
Run this and all your icons should start working again.