What is Microsoft's email for customer service?

Or is it something you have to pay for? I need help with my product Key, I have botten more windows cds then I have computer yet I can't put any of them on my new computer.

What is Microsoft's email for customer service?
You can go to this page:


http://www.microsoft.com/products/info/r...
Reply:http://update.microsoft.com/microsoftupd...