Right,
Power everything off. To start with you need to make sure that you have the stb plugged in via straight ethernet cable to the uplink or wan port of the router.
Then turn the stb back on. When the mcns light comes on solid (light on the middle panel) turn on the router.
Then connection one of the ethernet ports on the router to your computer with another straight ethernet cable. Then power on the computer.
There is no bridging of connections necessary, and probably no need to run through a setup cd. Delete any bridges that are appearing and then check the status of your local area connection. It should be enabled and connected. The click on status. You should then have an ip address appearing there, which will probably be in the form 10.xxx.xxx.xxx or 192.168.xxx.xxx. If this is there all is good.
Open the internet explorer and type the address 172.30.16.83 and press go. This will take you to a logon page asking for your PID and password to register the new device. Follow all instructions and then power everything down again. Turn all back on in the same order- stb, then router, then pc.
You will then have full internet access. And will be able to simply plug any other computers into the router and be up and running straight away.
If you have problems.... post back!