SOLVED: How To Fix or Manually Uninstall a Corrupt Microsoft Silverlight in Windows 10

If you have problems with Silverlight on Windows 10 or Windows 8, like being prompted to install it when you already have Silverlight, there are several steps you need to take to correct it:

NOTE: Silverlight does NOT work in Microsoft Edge so make sure you are using Internet Explorer 11 for all of the links below.

DETECT SILVERLIGHT:

1. Click THIS link to see if your browser thinks Silverlight is installed
2. Click THIS link to run a basic test.  If it tells you that Silverlight needs to be installed, Silverlight is likely hosed.

At this point you can confirm that your Silverlight is installed but bunged up.

UNINSTALL / REINSTALL SILVERLIGHT:

1. Close ALL Internet Explorer sessions, including this one
2. Click the START button
3. Click SETTINGS
4. Click SYSTEM
5. Click APPS & FEATURES
6. Scroll down to MICROSOFT SILVERLIGHT and click on it
7. Click UNINSTALL
   1. IF it uninstalls cleanly, you can launch IE and surf to THIS link to install Silverlight and be happy
   2. If it does not uninstall cleanly, move to the next section

VERIFY AND REPAIR WINDOWS FILES:

1. RIGHT click on the Windows 10 START button and select COMMAND PROMPT (ADMIN)
2. Type SFC /SCANNOW and press enter (not case sensitive)
3. Wait for the System File Checker to complete and then reboot regardless of what is says
4. Click THIS link to see if your browser thinks Silverlight is installed
5. If it does not, move to the next section

MANUALLY UNINSTALL AND REINSTALL SILVERLIGHT:

1. Close ALL Internet Explorer sessions, including this one
2. Delete: %ProgramFiles(x86)%\Microsoft Silverlight
3. Delete: %ProgramFiles%\Microsoft Silverlight
4. Use REGEDIT to delete all of the following entries:
   1. NOTE: Bunging up the Registry will blow up your Windows installation so be careful
      and credit to Microsoft Amy for starting this list off right, thanks!
   2. HKEY_LOCAL_MACHINE\SOFTWARE\Software\Microsoft\Silverlight
   3. HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Installer\Products\{D7314F9862C648A4DB8BE2A5B47BE100}
   4. HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\
      1. search through this for SILVERLIGHT and delete any references
   5. HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{89F4137D-6C26-4A84-BDB8-2E5A4BB71E00}
   6. HKEY_CLASSES_ROOT\Installer\Products\{D7314F9862C648A4DB8BE2A5B47BE100}
   7. HKEY_CLASSES_ROOT\TypeLib\{283C8576-0726-4DBC-9609-3F855162009A}
   8. HKEY_CLASSES_ROOT\AgControl.AgControl
      1. will have some version number at the end
5. Click THIS link to see if IE11 thinks Silverlight is installed and if it can be installed

If the above still does not work (and it has not for me at least once) you can blow 10 minutes searching the registry (F3) for every entry of SILVERLIGHT (which is what I did) or you can simply get a registry cleaner like RegistrySmoker Free Edition to remove all the dead links now that %ProgramFiles%\Microsoft Silverlight is gone.