I booted both systems from Knoppix 3.4 CD and was able to succcessfully ping each PC from the other. In addition, I found out that 192.168.0.1 is the modem address, 192.168.1.1 is the router address, and 192.168.1.100, 101 are the addresses for each PC. I was able to ping all addresses from each PC booted from Knoppix 3.4.

I also found out that Service Pack 2 was installed on my Windows PC so I uninstalled that because it has caused nothing but problems so far, and also because I have other means of protecting that PC.

The modem is a SpeedStream 5100 and I believe it does not have a built-in router. There is a self test option at the modem address (192.168.0.1) that allows you to ping addresses to test connectivity. When I tried to ping my systems while at 192.168.0.1, it timed out. But then when I pinged from the console it worked fine.

When I visit 192.168.0.1 I get all my internet service info. I can reset modem, changed modem codes, get loggs and statitics reports, check and change IP address assignment lease time, see MAC address, PPP location, PPPoE...

When I visit 192.168.1.1, this is where I can change all the router settings like DHCP, DNS, Static and Dynamic IP...

So I think you are right when you said it's a Windows problem. But then when I re-booted Windows without SP2 installed and making sure the system was not blocking pinging, it still didn't work. I even changed a setting at 192.168.1.1 where I can block WAN requests (pings) to allow for access to my system... I am not sure what is going on.

SBC is internet service provider, by the way...