I was a tad bored (writing a tedious document will do that to you), so I strung them along a bit, to see what they were really after. They said they could prove who they were because they had my computer registration number, and only the registered owner and Microsoft would know this (along a bit of gobbledygook about how this happened).
I said I thought they were a scam and that they were trying to sell me something. (I didn't ask how Microsoft knew my phone number to contact me about the problem.)
Aggrieved, they offered to prove they were legitimate by telling me my machine's registration number. I should turn on my machine and look at its registration number myself, and compare them.
I said: "But you've just told me my computer has a virus. So how do I know that virus hasn't downloaded the number to you? You having the registration number is therefore no proof that you are who you say you are."
Pause. Then they repeated of all the stuff about only Microsoft knowing the number.
So I repeated my reason for believing that their having the number would not constitute proof that they were who they claimed to be.
Pause. Then a slightly plaintive: "so what can we do, then?"
This was not providing me that much amusement value really, so I terminated the conversation, then Googled "windows phone call saying they know your computer id". Top hit was “Windows Support” Scam Worsens / Money Watch. From the comments it seems many people have much more stamina than I do for keeping scammers hanging on the phone.
Scammers are scum.
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