At My Digital Life you can read about Belarc Advisor spreading Windows license keys. Advisor is a system profiler which also includes the Windows key in its reports. Users posting them to the Internet also publish their Windows key. A common string of Advisor reports is “Belarc Advisor Current Profile“. Together with the desired Windows version you can easily find license keys:
https://google.com/search?q=”Windows+XP+Professional”+”Belarc+Advisor+Current+Profile”+key
This also works with EVEREST: