Clean / detect unused files C:\Windows\Installer

Install PatchCleaner:

PatchCleaner_1.4.2.0.exe

70d0bd7633d10c492839272c97b2544e

4da0e8c2fe1f06b13985d700fe15686a1015c3bb

Open applicaition:

Select backup directory and for safety purpose move unused files there:

Note:
This work very well on Windows 8.1.