Free& safe firewalls and virus killers

Free& safe firewalls and virus killers

I looked in the tags and memories and didn't see this so I am asking forgive me if its a repeat I am sick and not all here. Ok I remember back there was some talk or free firewalls and virus killing software that was free and worked better than norton. My mom's computer is fried so now shes using our tower and it has nothing on it and some site is already claiming we have virus and other stuff on it( we have a laptop we use so we were not using the desk top we have right now) we can't afford to go buy norton or any of that kind of stuff. What is free and worked well for you. I would be grateful for any information on stuff you have tired that works well. Thanks
My room is very cluttered and messy

My room is very cluttered and messy

Neato tree bark

Neato tree bark

Hi!

Hi!

So my mum decided she wanted to redecorate my room while I was at work.. :D

So my mum decided she wanted to redecorate my room while I was at work.. :D

Help! Sawfly caterpillars are destroying my hollyhocks >:(

Help! Sawfly caterpillars are destroying my hollyhocks >:(

Wilt

Wilt