I've had to deal with this for the first time, and my curiosity is really wondering what the specifics of how it works are. I've had a legit retail key for years, and I guess I've used it too many times online over the course of various PCs and I was forced to give the phone activation a try. 5 minutes later, it worked! So my questions are this 1) What's the science behind how it works? (how does it know the key pair, how does it work fully offline, etc) 2) Why would online activation not work, but phone activation work if its been used too many times? Do you get an "extra amount" if called in via phone? 3) Does this register it properly with the activation servers on M$ end, so if a reformat happens with the key the activation is picked up? Or does it require another call in? 4) Is the CID (Confirmation ID) they give you something that you can reuse indefinitely? If anyone has answers for any of these questions, i'd appreciate it! I just find it fascinating and haven't seen it touched on much.