1. The thread was moved to Internet Discussion from Desktop Computers
2. Routers have a basic firewall in them. Depending on how much marketing has got to the firewall, the definition of "firewall" (as far as routers go) might just mean "NAT" (network address translation) which is what the function of a router is: to make a private local network within itself and provide that network with access to the internet or another network
3. The primary purpose of a router (not them fancy IDS systems) is to "split high speed internet" amoungst different people. Any protection offered is coincidental, passive and incidental
4. A software firewall is designed to actively protect the system it's installed on from various forms of malicious activity. A router will let you goto WebsiteA but the software firewall will (attempt to) stop the malicious activity launched by that website