Troubleshoot Flash Player installation | Windows
http://kb2.adobe.com/cps/191/tn_19166.html
redirects to
http://helpx.adobe.com/flash-player/kb/installation-problems-flash-player-windows.html

Adobe Flash Player

Download uninstaller (close all web browsers before running "uninstall_flash_player.exe"):
  http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html
  http://download.macromedia.com/get/flashplayer/current/support/uninstall_flash_player.exe

Offline installers
  Internet Explorer:
    http://fpdownload.adobe.com/get/flashplayer/current/support/install_flash_player_ax.exe
  All other browsers:
    http://fpdownload.adobe.com/get/flashplayer/current/support/install_flash_player.exe

Verify Flash Player installed (may be browser-specific):
  http://www.adobe.com/software/flash/about