Occasionally, well, more that occasionally, whatever Adobe has posted to it’s Get Flash Player page for Windows fails to install. Here’s some tips, advice and links.
This is a particular problem on machines running 64-bit Windows and 32-bit Firefox for Windows, but not exclusively so.
Adobe knows this is an issue, hence this support document.
More coherent, albeit contentious, advice from Mozilla Firefox Help here.
User acrimony runs high in this Adobe bug report. Please people, don’t blame the programmers because they have bad management! They didn’t pick their leadership, after all.
Most of the time the problem can be resolved by downloading and installing the full runtime package (designed for enterprise IT distributions):
The packages here combine both the 32-bit and 64-bit versions into one for Internet Explorer and 32-bit “for plugin based browsers” (Firefox, etc.).
My practice on updating is to first uninstall all Flash and Shockwave products and then to install clean, first the ActiveX version for 64/32-bit Windows and Internet Explorer, and then the 32-bit plugin version “for plugin based browsers” from the above runtime downloads page.
Not exactly “user friendly”, but as most of my serious computing gets done on Linux — a platform Adobe has proudly announced it is abandoning after Flash v11 — I really couldn’t care. The only reason I still mess with this stuff is to help my immediate family.
To test your installation: