Hello,

If you downloaded Firefox from the official Mozilla website:

• https://www.mozilla.org/en-US/firefox/new/ , or
• https://www.mozilla.org/en-US/firefox/all/

Firefox will be 32-bit. A 64 bit version of Firefox is planned for the future:

• https://wiki.mozilla.org/Firefox/win64
• Note: All other 64-bit Firefox versions (other than Nightly and Aurora) are unofficial builds and not maintained or supported by Mozilla

For future reference, in 64-bit Windows, an easy way to find out whether an application is 64 or 32-bit to check the installation folder:

• (all 32-bit applications will be here:) C:\Program Files (x86)\
• (all 64-bit applications will be here:) C:\Program Files\

However, if you are using a 32-bit version of Windows, you will not be able to run 64-bit applications at all, and when you look in your C:\ folder you will only see:

• C:\Program Files\

Thank you for the fast response

The earliest Release there may be a Win64 Firefox from Mozilla.org is Firefox 37.0 in first phase. https://wiki.mozilla.org/Firefox/win64

It appears based on your useragent that you have 32-bit Windows XP.

32-bit Firefox on 64-bit Windows have WOW64 in the useragent to show it is a 32-bit application on 64-bit Windows.