How to get your Windows Product Key for free from Microsoft

I had this problem - I reinstalled Windows XP on my computer and when I was product to enter the Product Key, I couldn't find it! I waited until the next morning and when I got to work, posted a questions on the Microsoft Self Help Support and was told by a user "You will have to purchase a new Microsoft Product Key". Annoyed by this (it was complete rubbish as I found out later) I decided to call Microsoft and they simply gave me a new one, free of charge.

It was really simple:

Make sure you are at your PC, that it is switched on and is prompting you for the product key; have you genuine Windows XP CD ready. Phone Microsoft on 0870 60 10 100 and follow the prompts to speak to a customer services representative about Product Activation. Explain to the representative that you have lost your product key. They will ask you some questions about the CD you have to make sure it is genuine. Once the representative has confirmed that your copy of your Microsoft Product is genuine, they will give you a new Product Key.

As simple as that.