I'm helping my mother with her Win 7 system. She had an odd thing happen yesterday. She gets a call from someone with an Indian/Paki accent saying that her computer is broken, but they can help fit it. Puzzled, she goes over to her machine and, holy moley, there is a prominent warning message there that her system won't work. I think the scam is that she is supposed to buy software that will "fix" it. She politely declines and seeks help (me). Well, turns out that nothing is wrong that we can later see.
But how does this work? Presumably she downloaded something bad that pops up the warning, and then calls Mahmood to tell her give her a call and offer to sell some help.
I assume this is some well known online scam with some malware she accidentally downloaded. Name? Removal instructions? She didn't recall the exact message that popped up.