Buying windows key
You can obtain a Windows key without needing the entire disk. There are services and tools that provide the necessary credentials separately.
You are able to proceed. Then obtain Windows from Ms's website.
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Check Microsoft's site for a key or browse online stores like ncix, newegg, or Amazon.
Find keys on Reddit and G2A.com
Join the conversation on Skype using the same username as your forum account. Let me know if you need further assistance!