Windows 7 WannaCrypt Patch/Update

Running Windows 7 Professional. It appears that the proper patch/update for me to protect against the wannacrypt virus is KB4012215.

I reviewed my Windows Update history and see that I tried to install that update on 3/18/17 but the installation "failed."

I right-clicked on it and the Error Code is 80070020.

Questions:

1. 
   

   Is KB4012215 the proper update to guard against wannacrypt?

   
   


2. 
   

   If not, please tell me the proper update and where and how to download and install it.

   
   


3. 
   

   If so, please tell me where and how to download and install it.

   
   

Thank you.