This might be useful. I recently encountered an issue with IE8, and one of the member suggested me to run sfc /scannow
I have replaced my start orb, installed custom icons and patched uxtheme.dll to install 3rd party themes. Ran this sfc and unfortunately it replaced all my patched files with the originals. All my customization is lost.
I believe, you can try this sfc /scannow for fixing the lost icons too.