Who called from 4159726400

Didn't answer, left no message.

Keep getting calls from this number.They don't leave a message. I will not answer unknown numbers.

Got a call from 415-972-6400, didn't leave a msg either and google says it's Microsoft corporation.

Indeed, it is :
http://www.microsoft.com/about/companyinforma ... nfrancisco.aspx
Microsoft Northwest District: San Francisco, CA
Contact Information
Address:
555 California, Suite 200
San Francisco, CA  94104
Phone: (415) 972-6400
Fax: (415) 896-1458

As scammers spoof numbers, maybe they just found this one.

Received a scam call stating their systems were reporting an error originating from the Windows operating on my computer.  He didn't quite know what to say when I informed him I use Linux.