when installing FlashPlayer, I cannot go further than password step as it rejects my password.

I had to reinstall all my programs and data on a new drive as the old one crashed. When installing Flash Player, I cannot go further than password step as it rejects it. Yet the user name and password were accepted with no problem to access Adobe.

Strangely the same problem happens when I try to install and old version of Lightroom 4.

Can you help?