Elements 12 install

When I try to install Photoshop elements 12 in Windows7 I get a message "encountered an error while installing Shared Technologies" and the installation rolls back.

So far I have tried:

1.  Restarting my machine as suggested in a popup window during the rollback.

2.  Deleting the PDAppFlex files as suggested in Adobe's online help

3..  Downloading a new copy of Photoshop Elements 12

4.  Cleaning up my registry

I have searched for suggestions online.  Lots of people seem to have the same problem with no solution that works for many.