Code for gold not working

For your first question:

That will work.

A Gold code is a Gold code.

The promo code will not ilupgrade your account to gold, but will allow you to access gold features. Only some not all such as games with gold will not work with trial codes.

Hi there,

Remeeming errors are usually caused by issues on the account itself. Be sure to check your billing information at http://billing.microsoft.com and http://account.microsoft.com/services for any outstanding amount issues. After that try redeeming the code on
both xbox console and via xbox.com/redeemcode

Also check that account , console and code region match, using different regions van cause issues too.

If you can't find anything wrong and it is still not working, best thing to do is to contact official Xbox Support via Phone or Microsoft Support Chat at http://support.xbox.com/contact-us

it might be a problem on Xbox live's end, try again in a couple hours

If there is an expiration date on the code, it should say so on the card that has the code on it. Usually, its on the fine print areas. However, if you already have gold, then the code will not work anyways. it will only work if the gold account has expired
(at least in my experience).