You can use Xteq Systems
X-Setup to easily deal with your icon cache. Once you've installed the program, you'll have an expandable directory structure of all the available plugins. Go to "Appearance" > "Interface" > "Icons" and tweak one or more of the following:
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Icon Cache: Clear
Select an item to clear.
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Icon Cache: SizeEvery icon accessed by Windows is cached in the file 'ShellIconCache'. If this file exists, Windows reads the icons from the cache instead of searching for the actual files, which speeds up access time significantly, especially at bootup.
In certain cases a (too) small cache size leads to an incorrect display of some icons.
This setting specifies how many icons should be cached, the default value (also the minimum) is 500 icons, and theoretical maximum is 2000, but on some systems it is possible to increase this number up to 8000.
You need to restart your computer if you change this setting, and sometimes more than once, until the new icon cache 'catches on'.

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Reset Icon Customizations
If you have changed any shelled Windows icons, and made a mess of things, you can use this plug-in to remove all changes.
Please be aware that ALL shell icon changes will be lost when you click on the button!
Alternatively, you can click on the second button to only remove unnecessary entries - this won't change any customized icons but will get rid of references to 'uncustomized' icons.
NOTE: Some settings may not take effect until you restart the computer.
Hope this helps.
- M.
Edit: Forgot to close one of the quotes, and it was screwing with the display....