We dont have separate version for 64bit, thr current version of firefox works fine both on 64 and 32 bit

To be more accurate on what Swarnava said, Mozilla does not make a 64-bit version for Win64 specifically. They do make 64-bit versions for Linux and Mac OSX (combined dmg download).

User Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:19.0) Gecko/20100101 Firefox/19.0.

The WOW64 part shows you are using 32-bit Firefox on 64-bit Windows 8.

James - So to put it simply, if I'm using windows, I'm using the 32 bit version?

Yes, 32 bit version of Firefox.

Thanks that helped a lot, but what version of windows am I using 32 or 64. Java is constantly asking me. they seem to want me to say 32 . I think I have both but I'm not sure.

You are using 64 bit windows.

Billy you need to use 32-bit Plugins with 32-bit Firefox regardless of whether you have 32-bit or 64-bit Windows.

Start the Task Manager (Ctrl+Shift+Esc). 32-bit will have *32 next to it.

We dont have separate version for 64bit !! Just download the firefox .exe file and it runs on both 32 bit and 64 bit version of windows ..

sourav: I feel like I have to correct you on one small thing. True, we don't have a stable 64-bit version of Firefox, but we do have a 64-bit nightly version (which, in my opinion, has far better performance on a 64-bit system than the 32-bit version ever did). It can be found here: Firefox Nightly Builds FTP

ShadowMorph: This doesn't seem to be a stable version for windows. It appears that it could cause a lot of problems if your not a skilled coder and have a solid degree of skill in operating systems.

Where did you get that idea? It's pretty stable. Most bugs get fixed by the next day, and the most irritating ones get same-day patches. While they don't recommend you use it as your main browser, I have for a few years with no major issues.

My bad. I probably should try it before making a comment. I saw that it was a work in progress and.... SORRY

Firefox works fine on both 64bit and 32bit windows OS.There is no explicit builds for firefox x64 bit except if you are not using linux.The Nightly builds feature the absolute latest changes, and are considered unstable. They are the most buggy, and will result in a higher crash count than stable Firefox Releases. They are to be used for seeking bugs, and then submitting them to Mozilla developers, so that the Beta and Release channels do not suffer from such bugs.

Nightly is usually many versions ahead - Currently on 27. So you will be seeing features added long before others, but at the risk of crashing more, and potentially broken parts of Firefox. I can confirm this by using x64 Nightly and not being able to use Flash properly anymore (Crashes x64 Flash)

They are to be used at your own risk and discretion. As they say, "These builds are for testing purposes only."so don't count on Nightly when working.

Thanks for expressing your opinion of nightly build. It was pretty much what I was trying to say, but you expressed it better. It's not very stable and can cause problems you need the skills to work with and fix.

As to Flash it seems to be causing problems everywhere. I'm constantly getting request to upgrade. Apparently I answered one that I shouldn't of have and got one that's trying to take over all of my upgrades. I ran Malwarebytes' Anti-Malware and had 2 hits. Although only PUPs I removed them and am now having problems with installing downloads.

I'm getting off topic so I'll close my reply, but thanks SumantroMukherjee, I don't feel so incapable of posting now.