The purpose of a router is to share the Internet connection. If you only have one PC you don't need a router. Either way, you want a firewall, antivirus, and antispyware/malware software installed.
I have the option of connecting to the Internet either with ethernet (using a modem) or wirelessly (using a router). Which one gives better protection from viruses/malwares ? I understand routers have 2 IP addresses and although am not an expert in this field, I am suspecting the router adds firewalls over above Windows firewalls. Pls correct me if I am wrong. Thanks.