Get Genuine Windows Agreement
http://www.microsoft.com/presspass/features/2007/oct07/10-02ggwa.mspx
If it was not hard enough to work with Microsoft, here's another wrinkle…Microsoft just announced a licensing program to help corporations who may have been the victim of piracy or counterfeiting get legal. In most cases this is directed at clients who already thought they were legal.
Abbie and I recently took and passed the Software Asset Management exam and can attest to just how hard it can be to be legal with your software. This is a real problem for us businesses, the Business Software Alliance research indicates that North America has a 22% Piracy rate: http://www.bsa.org/country/Research%20and%20Statistics.aspx. While that's not as bad as other parts of the world, it's still pretty shameful. For your business, think about being robbed for 22% of your stuff. I don't know how much the big box retailers consider acceptable loss rate, but I would be shocked if it were that high. I am glad that a) Microsoft recognizes that not all this piracy is willful and b) that they are taking steps to help customers know and understand their rights and obligations and how to become legal if they are subject to a shortfall.
If you feel you may be a victim of Piracy or want to learn more about this problem feel free to contact either Abbie or I about this and we'll try to help.