hello coree, adobe is offering various work-arounds for installation problems for its flash plugin here: http://helpx.adobe.com/flash-player/kb/installation-problems-flash-player-windows.html

Sometimes the Windows installer gets too many changes queued and stops working correctly. In those cases, it usually helps to shut down and restart Windows to clear the backlog.

For future reference, the Flash player plugin should install to this folder:

C:\Windows\SysWOW64\Macromed\Flash {based on Windows 7 64-bit}

You want to find NPSWF32_11_9_900_117.dll

Manual installation of Adobe Flash(player)
Use Firefox to go to the Adobe link in the article below and follow the instructions in the article. Click on "Installing the Flash plugin manually" in the Table of Contents.

• https://support.mozilla.org/en-US/kb/install-flash-plugin-view-videos-animations-games

You also need to update Adobe Reader to avoid security issues in the version that you are currently using.

• See - https://support.mozilla.org/en-US/kb/use-adobe-reader-plugin-view-or-download-pdf-files