internet connectivity issue

I have an internet connectivity problem. ISP is Comcast, modem is Motorola SB5100, Windows 98SE. The problem is that there are several sites (at least 11) that consistently time out. I’ve spoken with many technicians at Comcast but they have been unable to help. I’ve: disabled the firewall and antivirus, reset security settings to default, release/renew lease, cycle modem, reinstall browser, reregister modem, etc. The sites are consistent and browser doesn’t matter (IE and Mozilla). Traceroute to the sites in question have the same results – first hop times out, 2nd and 3rd hop are Comcast ips, 4th hop is 12.118.239.57 and results in “Destination net unreachable”.

Any help or suggestions would be greatly appreciated.

Angela