If you have a legitimate copy of Windows installed and working you can retrieve the product key from the registry using this program - http://www.magicaljellybean.com/keyfinder/
This will not work if your computer came from the factory with Windows already installed. It will find a product key but it's useless and won't activate.
I use this program when the COA sticker is stupidly placed on the bottom of laptops and gets worn down so badly you can't read it. Don't be so quick to judge people as thieves and pirates