Wow, I found this thread here and fixed it:
error 1719 windows installer service could not be accessed .... - Microsoft Community
Now for me I did not have this key so I created it, bounced the PC and everything is working. How crazy is that?
Very weird. I am running Windows 8.1. The other day I come to find my nvidia and Bosto drawing tablet drivers hosed. I proceed to try to install new ones which seemed to work. I noticed when trying to run Windows update it hangs on installation. Then it seemed to apply to almost anything...