You can play Battlefield 3 online. You might need to insert another BF3 disc than the one you currently have. Also make sure your game console is connected via your Ethernet cord.
your cpu sucks
Yes, you do.
Yes, why would they not.
No
Yes, XBOX live, or "online play" is included.
Kids can play battlefield 3. From what I know you are not able to play online unless you are 13 years or older. Unless you put in a fake birthday then you can't play the multiplayer. Also if you want to know whether your child should play look at the rating. For Battlefield 3 it is M+ for 17 and up. So, yes they can, but it is not suggested.
No you cant.
You have to be 13 years old to play on the multiplayer for Battlefield 3.
You can't. You have to connect through either PSN or XBox Live.
Assuming you have an Internet connection subscription, yes. You do not have to pay to play PC games online like you do for Live or PS Network.
You can play the Battlefield 3 Co-op campaign,but there is no co-op like there was in BF2 with bots.
No you cant