Should I still use my router?

I used to trade with 2 computers connected by a router. I gave one of the computers to my brother, so I only trade with one computer now. Is there any reason why I should still use my router.......Does it provide virus protection.....or is it just slowing down my internet connection now and serving no protection? Router or no router?

 

Yes, use the router. It will not affect speed, and it is a firewall.