The D7000 is a DSL modem router but it should still work. It's best to log into it and force the router to use the Ethernet port under ADVANCED > Setup > WAN Setup and in WAN Preference selecting Must use Ethernet WAN (which also causes the DSL port to be disabled).
So, with the hub in modem mode (LED must be magenta) connect the D7000 by its WAN port to the hub and reboot the D7000.
You seem to suggest your connecting your PC to one of the Hub 3's ethernet ports as well as the Netgear d7000, so that would be wrong.
Previous Super Hubs would only allow you to use one ethernet port for modem mode, but I think the Hub 3 now lets you use any port, by connecting two devices then the first one to get issued a IP will probably connect to the internet, so if the PC wins that race it'll work on the net, but the Netgear will not. (I have not tested how this works on the Hub 3).
Basically. Put the Hub 3 in modem mode, The only ethernet cable to the Hub 3 should go to the red port on the Netgear d7000, reboot the Hub 3, do not connect any other wired devices to the Hub 3, connect all new wired devices to the Netgear d7000. It's likely at this point everything wired will work, but on one of the wired devices go to www.routerlogin.net and it will probably set things up automatically for you.
I know it may sound obvious, but don't connect anything to the phone port on the d7000 - That's for xDSL customers.
The Quick Connect guide that probably came with the d7000 likely shows how to set it up for DSL. If you look in the larger booklet (if provided), if not then look here http://www.downloads.netgear.com/files/GDC/D7000/D7000_UM_EN.pdf starts at the end of page 29, then it shows how to connect to a service that has a modem.
I'll be honest, the instructions for the d7000 look really bad (welcome to Netgear), but they do provide the info you need. There may have been a IP conflict during startup too depending on how you had things connected, but I will assume for now that's not an issue.
If in doubt, Reset button on them both and start over - Just don't connect anything to the Hub3 other than the red port on the d7000 and you'll eventually get it going ;)…
---- I do not work for VM, but I would. It is just a Job. Most things I say I make up and sometimes it's useful, don't be mean if it's wrong. I would also make websites for them, because the job never seems to require the website to work.