Thanks for the links to ESR Firefox, but the download links to the 32 bit download won't work. I tried it in Safari, and IE. Any suggestions? Can't I just use the regular Firefox?
No, Firefox 53 was the last regular version of Firefox that was supported on Win XP SP3 and Vista SP2 and all users with these older operating systems were automatically switched to the Firefox ESR branch in March 2017. The support article Important - Firefox is ending support for Windows XP and Vista notes that Mozilla will continue to support Firefox ESR on these older platforms until at least September 2017 and "In mid-2017, a final support end date will be announced based on the number of users still on Windows XP and Vista".
When I browse to https://www.mozilla.org/en-US/firefox/organizations/all/ with Firefox ESR v52.3.0 I see
Firefox ESR Download Mozilla.png 58.72KB
but I can confirm that when I browse to that same URL with my IE9 browser I am redirected to https:// download-sha1.allizom.org/?product=firefox-52.3.0esr-SSL&os=win&lang=en-US and see a "The webpage cannot be found" error, so it appears IE9 can't establish a secure connection. That might have something to do with the fact that IE9 doesn't support newer (and safer) protocols like TLS 1.1 and TLS 1.2 for connecting to secure https sites. If you browse to the Qualys browser security test site at https://www.ssllabs.com/ssltest/viewMyClient.html using your IE9 browser you'll see all sorts of red warnings about protocol support and exploit vulnerabilities that you won't see with the latest Firefox ESR.
IE9 Qualys Browser Test 17 Aug 2017.png 23.18KB
The good news is that I was able to download the latest ESR installer (e.g., Firefox Setup 52.3.0esr.exe) from Mozilla's FTP server using IE9. For 32-bit operating systems go to https://archive.mozilla.org/pub/firefox/releases/52.3.0esr/win32/ and then choose the link for your region/language. If you want the US English version, for example, the correct 32-bit installer will be located at https://archive.mozilla.org/pub/firefox/releases/52.3.0esr/win32/en-US/.
Further to my previous comments about downloading installers from Mozilla's FTP site, I did some more testing and discovered that the link https://www.mozilla.org/en-US/firefox/new/ will auto-detect my Vista SP2 OS and download the correct Firefox ESR installer when I use my IE9 browser.
32-bit Vista Home Premium SP2 * Firefox ESR v52.3.0 * NS Premium v18.104.22.168 * MS Office 2003 Professional SP3
Edited by lmacri, 17 August 2017 - 08:58 AM.