Is there a free anti-virus from the internet that is not just for a trail period?

I use Avast for anti-virus, which is free, and to compliment that, I use Malwarebytes Premium.  I pay a yearly subscription fee to use Malwarebytes Premium, but Malwarebytes protects more against malware, spyware, and ransomware.

Malwarebytes is free, but with premium you get 4, real-time shields that protect you at that moment.  So if I accidentally click a link I didn't want to click, and that link has malware that is a browser hijack, Malwarebytes Premium will stop the connection before it even happens, and I won't get infected.

With the free version of Malwarebytes, you won't know if you're infected until you run a scan.  But Malwarebytes I have never seen as being an anti-virus program specifically, which is why I run Avast and Malwarebytes.  Plus, Malwarebytes Premium runs a daily scan.

And no, running both of these programs does not slow down my computer.

Assuming you are running Windows 10, it already has a build in anti-virus.  There is no need to add an additional anti-virus to the computer.  All it will do is slow your computer and not make you any safer.

A large number of antivirus are available and are free to use. They are also very good at protecting your computer: Avast antivirus,Panda antivirus,Kaspersky antivirus, Comodo antivirus, and Sophos home antivirus.

avast is free , thats the one i use .

There are many free ones available which aren't just for trial periods but are fully functioning versions of the paid-for program and use the same databases. Some are already mentioned here. 

The paid versions offer extra functions which may or may not matter to you. The protection which comes built-in to Windows is now better than it was but still not up there with the others, mainly because it does not update frequently. 

I saw Windows Defender on a bike trail recently.

I have never used one while on the trail.

Yes, as some of these programs are trend micro and just other cool ones.

yes the free Avast anti virus

Yes. AVG and Avast are free antivirus. But I would suggest to go with paid one for more security.

here are some free ones - Avira, Avast and AVG, although there are plenty of others they are the ones I have used in the past, presently I use Malwarebytes Premium, I have a lifetime licence because I bought it many years ago when they gave people lifetime licences

Try AVG or Avast Both free and Both good

Nothing wrong with windows defender and if you get internet through a cable provider they might even have free anti virus .

I don't know.. 

If no online  financial transactions is done  then, Windo's in-build AV is sufficient to protect a PC or phone. NoScript add-on extension can be an option for most browsers.
Beeter still start using Linux OS like Ubuntu etc ! :)

AVG free. it bugs you with adverts now and then but it works

Yes it is. 360 Total Security

Windows Bit Defender(or a name close to that as Microsoft saw it had to write a program for the computer and supply the updates to ALL the versions of Anti virus out there.  They get their updates from M$ when it knows.

Avira is free.  It is the red umbrella one.

Assuming you are running Windows 10, it already has a build in anti-virus. There is no need to add an additional anti-virus to the computer. All it will do is slow your computer and not make you any safer.

Yes. Malwarebytes. And it is very good. You can also buy the deluxe version of it which offers more protection, but the basic version is free. 

I used free anti virus software for years and always ended up with a virus eventually. I think the free stuff is like out of date software or something the apprentice came up with. It had some holes.
For the past 5 years I’ve paid for it (Kaspersky) and haven’t had a single problem.

These have free versions of their paid anti-virus software and are very good: Bitdefender,Avast,Avira,AVG,Panda Dome,360 Total Security (extra tools) and their 360 Total Security Essential (anti-virus only),Kaspersky,Comodo Anitivirus (and a free firewall if you want it),ZoneAlarm Antivirus and firewall.

Yes, there is Avast antivirus which is free. You can go through with that. 

Yes there are.
AVG, Avast, Panda all offer free anti-virus without subscription or cost.

AVG Antivirus free is one of the most popular antivirus programs on the market.
Avast has one of the most popular antivirus apps around, due in part to offering a free version, and it's one that performs respectably.
Panda Free Antivirus is fast and free, boasts the top score in real-world protection, and offers a USB drive cleaner.

All and more available at Download.com
https://download.cnet.com/s/security/

There are many excellent free products. This site is a good place to review them: 
https://www.pcmag.com/picks/the-best-free-antivirus-protection 

You plan on using it when you hit the trail?

AVG is, but anymore Windows Defender is pretty good for Windows and it comes with windows and usually is active when no virus software is present. 

Yes.  Lots of them.  HOWEVER -  If your using Windows 10, you don't need a Third Party Anti-Virus as Windows 10 has it's own called Windows Security (Defender).