[B][/B] Region : Canada

Model : TD-W8968

Hardware Version :

Firmware Version : 2.1

ISP : Bell Sympatico

Device that's giving me grief is TP-Link Wireless N ADSL2+ modem router. Has worked just fine with the exception of the fourth port, which will not allow a connection to the internet, and I've tried everything. The other 3 ports were in use and would connect fine, as well as the additional four machines that connect wirelessly.
So basically I have a 4+4 setup with everything working fine except for the fourth physical port. I can see the router light flashing and corresponding with the LED light flashes on the pc as the machine boots and tries to connect. The cable's fine, the feed is getting from the pc to the TP-Link, it just won't allow an internet connection. And get this, to rule out any problem with the TP-Link fourth port itself, I tried a wireless connection from that pc, and still no internet.
Firewall is Off.

Next I tried the identical 4+4 setup on a different wireless router and all machines connected to the internet just fine. That was a straightforward transfer of cables out of the TP-Link into the other modem - no problem with any of them.

I've tried the latest drivers for the Realtek Local Area Connector on the motherboard on the machine in question, no difference. I;ve updated the TP-Link with the latest from the site.

And here's the latest weird thing, I can log on to the router from that machine when I type 192.168.1.1 into a browser.

I don't get it, 7 machines connect fine, 1 doesn't whether via cable or wireless, then all 8 connect flawlessly when a different wireless modem/router is used.

Open to all fixes and ideas, folks, and the modem/router I've been falling back on goes back this week (switching ISP's) Thanks for any help!