Hi Steve and welcome to the forum. Take some deep, calming breaths...
You say you have an Adwords account you used to use. What does it look like now? Are you able to log in to the Adwords interface? Can you see your old campaigns? I'm presuming the answer is yes if you've changed your credit card details.
Can you see any messages displayed at the top of the interface window?
When you say "nothing is happening", can you be more specific? What is it that you think should be happening? Are you not seeing your ads or is something else amiss?
Some great thoughts from Jon there, if it's your ad showing that you're worried about the Ad Preview Tool could help you out, but feel free to give the Community a little more information on your issue and we'll try to help you out!