...You will have to decide if you want to use a paid or free antivirus. If you want a free antivirus I know that Avast Free Antivirus v18.8 (the legacy version for Win XP and Vista that is available for download <
here>) is a popular choice, but if I were still using my Vista SP2 machine...I would probably beef up my protection and use one of the paid antivirus products....If you want a paid antivirus....I thought Norton Security v22.15.x...was a good choice for Win XP and Vista computers, but....I'm not a fan of the current Norton...product line...so I currently use the built-in Microsoft Defender antivirus on my Win 10 laptop...
I ran Vista for 12 years, and
never once paid for an antivirus! The last AV that I used on Vista was the above-referenced Avast Free 18.8 (together with a legacy version of Sandboxie for browser security - however I never tested SB with the “fringe browsers” that XP/Vista diehards must resort to now). For those who only feel secure when their bank balance shrinks, Avast/AVG also made paid versions including a firewall etc, but were they really any more effective? There are independent labs who test and rate AV products. One of the most renowned is
AV Test, and here’s a link to their
October 2018 test results on Windows 10. (No lab has bothered testing on Vista in a very long time. Why October 2018? Because various products were at or near their final Vista-compatible versions then. Of course most of the tested products had already ended support for Vista by then.)
The first thing I notice is that Avast Free and AVG Internet Security (paid) scored
exactly the same. This is not surprising, since they had
the same engine. (Sure the AVG version had a two-way firewall; but if you’ve got malware trying to phone home, then your AV
already failed.) The all-important Protection score was 5.5 out of a possible 6. (Avast Free scored a perfect 6 in
December 2018 when 18.8 was tested, but 5.5 was more typical.)
The next thing I notice in the October 2018 results is that Malwarebytes Premium (a paid product that has been discussed endlessly at this forum) had a Protection score of only 4, which was
the lowest of any product tested! True, there were other paid products that scored a perfect 6, such as Kaspersky Internet Security 19 (which
was compatible with Vista) and of course...Norton.
Imacri and wither 3 have persistently advocated Norton for years and years at this forum, and newcomers like
@mollytown might get the impression that Norton is the consensus choice among Vista’s remaining users. Quite the contrary! I’m a member of other forums such as MSFN, and the only person I know of who is
still using Norton on Vista
or XP (which has far more users than Vista) is wither 3, whose recent posts in this thread might constitute “the canary in the coal mine.” Be advised that Norton moved their XP and Vista users to
Maintenance Mode in June 2018, meaning that their actual current versions for Windows 7 and above haven’t supported Vista for 5 years now. Not only that, but Norton already threatened to cut off wither 3’s definition updates in February 2021, but changed its mind at the last moment.
Which non-Chinese antivirus will support Vista the longest? My guess would be Panda (based in Spain), which still
fully supports XP and Vista, i.e. you could actually use their
current version. Panda’s protection is cloud-based, so there is no need for definition files signed with insecure SHA-1 for the sole benefit of XP and Vista diehards (a key point). Panda has both free and paid versions. I used Panda Free for a while on Vista, but that was more than 8 years ago now.