iskysoft converted all of my pdfs

I recently downloaded iskysoft, not really knowing what it was or what it could do.  Before I knew what was happening, it converted all of my Adobe icon pdfs to iskysoft pdfs.  I immediately uninstalled iskysoft, but it still did not covert the pdfs back to the state where they all bear the red adobe icon.  I want the adobe icon to reappear for every pdf in my files.