Very persistent "Microsoft Windows" scammer called me 5 times in one day. Standard boiler-room script that sounds very dire and urgent. Joke was on them, my computer is so riddled with malware and viruses right now they couldn't access anything. And they tried - average call time was 10 minutes each time before they realized this was a lost cause.
Typical Windows support scam. When I get these, I immediately say "yes, this is tech support, If you'll give me your credit card information, we can get started." Stops 'em in their tracks, haha.