This is a common scam: Say "Windows," be exempt from the no call list as you're in Calcutta, and scare someone into buying a product or allowing them remotely into your system where they can make a damn mess. It is dangerous and targets, for the most part, elderly folks who can barely check their email. So fuck those callers.
Me? I animatedly enjoyed the conversation, injecting many "oh yeah?" and "wow!" celebrations while making absolutely sure the very detailed instructions would not directly hurt me. She sent me to the Event Viewer and showed me common errors and warnings not important even enough to show up on my screen. I was very nice and very patient, and when she lied about what those warnings were and the dangers they presented, I asked her to "wait" when she gave me the next instruction, carefully cupped my hands around the mouthpiece, and in my best demon voice said:
WHAT YOU ARE DOING IS SCARING AND HURTING OTHERS. STOP OR YOUR FAMILY WILL BE CURSED. STOP OR YOUR FAMILY WILL BE CURSED.
So... to much? What have you done to play with telemarketers?