Microsoft is ending support for Vista April 2017. No matter what browser you use, there will be no updates for Vista and it will be insecure. You should upgrade to Windows 7 or later.

However, there are currently no plans for Firefox to drop support for Vista, so Firefox will continue to receive updates. However that will still leave you with a secure browser running on an insecure operating system.

Thank you!

One of the best-kept secrets of personal computing is that Windows Vista is a perfectly good OS, however much those who are still running XP may despise it. Vista has much more in common with Windows 7 than with XP. As millions of XP users have amply demonstrated, having an unsupported OS isn't all that bad as long as browsers and antivirus software continue to support you. I'm not a Chrome refugee, but rather an Internet Explorer diehard who finally saw the light last year. Purchasing a Windows 7 disk from some unknown party and wiping out my superb system in hopes of getting another 33 months of incredibly slooow security updates doesn't strike me as a very good idea, so Long Live Firefox!