Couldn’t find this anywhere on the net, and took me a while to figure out myself so thought I’d explain just how to unlock the small “visual flair” that Bungie talked about before the launch of Reach.
What you have to do is to log into Bungie.net with the email address and password associated with your Xbox Live Gamertag, once logged in you need to navigate to your profile and you need to select “Game Settings” from the three tabs in the middle of the page – choose “Nameplates”
At this page around half way down is the input box where you need to enter your Halo PC product key, one entered click submit and your product key will be verified.
If all went well then you will be able to activate this Nameplate
And that’s it! Took me a while to figure out and like most people I tried to enter the product key in the Xbox Dash which of course didn’t work.. Which I bet most people did.