http://answers.microsoft.com/en-us/protect/forum/mse-protect_scanning/i-just-got-a-call-from-someone-saying-they-were/df4b9c12-422d-41e1-a255-624262426071
http://askleo.com/i_got_a_call_from_microsoft_and_allowed_them_access_to_my_computer_what_do_i_do_now/
I searched on:"i got a call from microsoft"
They will direct you to a specific website, at which point they will hijack your computer and hold it for ransom if you don’t pay them $$$.