You have to first update the game over xbox live
You cant lower your weapon in multiplayer you can only do it when you change your network settings to local.
Singleplayer: you cant Multiplayer: you customize your settings and T is the default button
You can change your username in settings.
you cant do it on campaign only on multiplayer
You can, you just have to play Combat Training in multiplayer, you only fight computer players unless you allow others to join you.
in campaign you cant but in multiplayer and online you can. go to options and edit your person
check family settings
You cant you have to have a completely different connection
You cant
You cannot able to change it.. When you write: "i agree for.." you agreed that your birthday date is correct and you wouldn't change it.. the only solution for this, it's opening a new account :/
You cant exactly make a gun in black ops, but you can customize a gun in multiplayer create a class mode and play online (or offline) with the customized gun.
You cant