it is best to avoid windows 10 right now, but i don't think this is the case, of the first hacking attempt from microsoft, so it most likely that you were infected
you visited a shady website or probably downloaded something malicious, in other words it's your fault
What about the passwords?
I've never entered them on Windows 10
Was your wallet encrypted? Someone found your private key, this is the only way to make transactions on the blockchain. guessing a bitcoin private key is impossible. The question is how the attacker found the key. I think the computer has a rookit or trojan.