No ethernet connection to internet via cable modem nor router

Greetings. Like a number of people have posted, I have the same problem of
being unable to get a network connection when my nForce4 Asus A8N-E's
integrated nic is connected to my Netgear WGT624 router. Knowing about the
SPI issues (though mine's disabled, which people say hasn't always made a
difference) and since I've not yet updated the firmware in desperation, I
decided to bypass it and connect directly via my Comcast Thomson/RCA cable
modem. As most people have been connecting fine via direct modem hookups, I
figured it'd work fine, but nope. I get the same limited connection messages
and inability to hit the internet at all like with the router. I couldn't
even log into the router itself when it was connected, and my XP laptop
confirmed via a wireless login that the router didn't see the Vista box as a
connected device. The PPPoE option for building a new broadband connection
is useless for me as I should just be fine with DHCP as in my XP Pro
dual-boot. I'll be trying k600r's suggestion of diabling protected mode
under internet, intranet, and trusted sites when I return home this evening,
but since most people aren't having these issues with a direct-to-cablemodem
connection, is there anything else I should attempt aside from this,
disabling IPv6 & network seeking options, and perhaps entering the DNS info
manually? I've already done an orderly shutdown and restart of the modem,
router, and attached devices before. Thanks for any input. Hopefully some
patches will be out soon to fix these TCP/IP stack issues.