Antivirus software, now often referred to as security (suite) software, due to the innumerable threats, come in a variety of different brands. To get an idea, check out the top ten sellers at Amazon (see source links below).
I personally use a FREE antivirus program called Bitdefender Antivirus Free Edition; however, you may feel more comfortable using one of the paid commercial versions such as reflected below.
Antivirus software was originally developed to detect and remove computer viruses, hence the name. However, with the proliferation of other kinds of malware, antivirus software started to provide protection from other computer threats. In particular, modern antivirus software can protect from: malicious browser helper objects (BHOs), browser hijackers, ransomware, keyloggers, backdoors, rootkits, trojan horses, worms, malicious LSPs, dialers, fraudtools, adware and spyware. Some products also include protection from other computer threats, such as infected and malicious URLs, spam, scam and phishing attacks, online identity (privacy), online banking attacks, social engineering techniques, advanced persistent threat (APT) and botnet DDoS attacks. [source: Wikipedia]