for paid antivirus i choose Kaspersky (you need more higher computer spec, such memory & processor)... for free antivirus i choose AVG (it's simple but powerful for home PC)
If you have a licenses Windows you can use a free antivirus software provide by Microsoft: Microsoft Security Essentials. Now I use this AV with a paid malware program Malwarebytes. With this 2 software I don`t have any problems , and my processor is not overcharged.