My solution :
After trying most of what was recommended (system restore, registry edits, rebuilding iconcache.deb in several ways) none of which worked, I finally got my icons back !!!
Go here: http://www.stardock.com/products/iconpackager/
and get the trial version of IconPackager, install it, use it to switch to any icon package, then switch back (if you want to) the standard windows icons.
And voilà... all icons back.
Best regards !