253-243-1407

With a VERY heavy accent, said he was with "Windows Operating System."  I said Microsoft, he said "Oh, No. Microsoft is only the manufacturer. We are with the Windows Operating Company in California.  We have been getting regular error reports from your computer.  Please go there right now and our technician will walk you through how to correct."  I said I would have my IT technician call.  He said, "Oh, No, you do not need any IT person.  We can walk you though"  I said "How did you get this telephone number?" He said "it is the number connected with your computer.  We also have your computer's ID number."
I had changed telephone numbers at the beginning of 2014 and this was NOT the telephone number I was using when my
IT guy installed Windows on my computer.
I took his number 253-243-1407 and did not do anything he asked. 253 is also the international area code for Djibouti, in Ethiopia.

Common IT scam operating out of India.  Been around for a while.  Be wary of anyone with an Indian accent offering you something or threatening you.