I have recently opened a new computer repair business with a primary goal of performing quality repairs at a lower cost than the competition. One issue I'm running into is Windows activation. After reading through countless forums, I have the following understanding of retail keys: They may be used on multiple computers, as long as a single key isn't activated on multiple computers at the same time. How is this determined? As in, if I decommission one computer, can I immediately use that retail key? My second question is how are OEM keys paired with a specific computer? More specifically, what component of that computer? Thanks for the clarification!