hi friendlyskys, the browser you've used to post this question was 64bit firefox, so yes it appears to be working :-) you can recognise it from the bold part in the user agent:

Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:43.0)...

32-bit versions of Firefox have "WOW64" in the user-agent. 64-bit versions of Firefox have "Win64" in the user-agent.

So according to the user agent, I also installed the 64-bit version of Firefox (Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:43.0) Gecko/20100101 Firefox/43.0). Two questions though:

1. Why doesn't it install to C:\Program Files\Mozilla Firefox instead of C:\Program Files (x86)\Mozilla Firefox 2. Why not show the architecture in the Help>About dialog?

Thanks!

To clarify my earlier post, I was surprised that the 64 bit version of Firefox installed in the 32 bit Program Files location (x86). I expected it to install to the 64 bit Program Files location. But that was confirmed by someone in another thread, who said that you don't have to uninstall the 32 bit version before installing the 64 bit version, since it installs over the previous version. But I still find it strange, and didn't know that doing so was possible.

I think that it would be best to uninstall the 32 bit Firefox version before installing the 64 bit version to ensure proper installation in the correct folder for the 64 bit version or otherwise do a custom install. It is possible to have both versions installed for the case you need to use plugins other than Shockwave Flash and Silverlight.

cor-el said

32-bit versions of Firefox have "WOW64" in the user-agent. 64-bit versions of Firefox have "Win64" in the user-agent.

Where is user-agent? I will look in the "about:config" but if I'm not supposed to go there under threat of breaking my computer, what is the point? I do believe that whether I'm running the 32bit or the 64bit should be in the version information at help about! And why on earth have wow64 in the user-agent when the convention is x86?

I think that it would be best to uninstall the 32 bit Firefox version before installing the 64 bit version to ensure proper installation in the correct folder for the 64 bit version or otherwise do a custom install. It is possible to have both versions installed for the case you need to use plugins other than Shockwave Flash and Silverlight.

Holy cow, could you be more ambiguous and the installation routine less than friendly? If the old version needs to be uninstalled, that should be in the install agent! Please understand that I don't know if I need to use other plug-ins; are you referring to ANY plug-ins or just video plug-ins? If I do come across something that doesn't like Flash or Silverlight, am I going to need to exit the 64bit Firefox and re-access the site using the 32bit?

If it weren't for the fact that I can't get java crap to work on the 32bit, I'd say why the hell would I want to install the 64 bit anyway? I think that the best course is for me to see if the site that wasn't working will under Edge or IE 11 or Chrome; if it does it's gonna be "bye bye mozilla".

You can type about: or about:support in the Location (address) bar to see your useragent. Or you can go to Help > Troubleshooting Information. A easy about url to remember is about:about

WOW64 means it is a 32-bit application running on 64-bit Windows. https://en.wikipedia.org/wiki/WoW64

The 64-bit (Win64) Firefox needs 64-bit Windows 7, 8 (8.1), 10 to run. It will not run on 64-bit WinXP, Vista and servers as you will need to use 32-bit Firefox.

Firefox on www.mozilla.org has the 32-bit version served to Windows users so if you want the Win64 Firefox go to the Systems & Languages link which is www.mozilla.org/firefox/all/