I had to take my old router with hardware firewall out of the circuit because it kept conflicting with my cable modem. But I just got a D-Link wireless router (DI-624) and it works like a charm. Now my kids and I can access the net with my desktop and three wireless notebooks all at once.
A LAN of some kind is a necessity these days, and the new wireless equipment is easy to set up.
Just for fun access the router log
( Check you manual, or try http://192.168.123.254/ )
and see how many "unrecognized attempts" are recorded- mine gets scanned by dozens every hour. It's a jungle out in netland.
When I reformatted & reinstalled on this machine a couple of months ago, the first thing I did was install AVG, then go to MS to update & patch the OS, and in that time, four different viruses tried to install themselves, despite the firewall in the router.