Xbox live silver

You are showing as a silver member, you cannot play on Xbox Live as a silver member.

if you did it correctly you should have gotten the free 30 day gold trial if not then your silver

- Sign up for Xbox Live Silver.

- Choose Xbox Live Silver Membership for $0.00 even if you like to have Xbox Live Gold.

- It will ask you if you are sure you want to continue with only the Silver Membership.

- Choose the "Keep Silver" option to continue with the set-up.

- Then it will inform you that you are now eligible for a free 30 day Xbox Live Gold Membership.

- Enjoy the free trial and make sure to keep the upgraded Gamertag account.

My another question is that, How to recognize the xbox live silver card and xbox live gold cards? Is the silver card still available.

Can i use xbox gift card to buy a gold membership?

@Theory of Game is correct. An Xbox Live Gold subscription is required to play any multiplayer games online, regardless of the console. You can get an Xbox Live Gold subscription by managing your subscriptions in your account at
account.microsoft.com/services

Think of it as a trial version. Everything that is done via Xbox Live costs Microsoft to run those services. Since we're paying for a Gold Account, you're putting your portion of the money in for Microsoft that allows you to have all these nifty features.
Some people only make Silver accounts for Zune, Netflix etc, but they pay themselves when they use the app.