The VRG forums require that you either use your full name as your username, or add your name to your signature.
There is a how to on changing your signature here.

Here, we will cover changing your username. Doing so will change your name on all posts you've already made, so you don't have to worry about your old username appearing.

Click on the User Control Panel:


Then click on "Profile" and "Edit Account Settings"


In window you will now see the "Edit Account Settings" window, and your current Username will be in the Username: field. Replace this with your new username, and then enter your current password in the "Current Password" field. This is necessary to confirm you want to change your name. Then simply click "Submit" and your username will now be changed!