this is a scam, under no circumstances should you call any number on your screen, MS would never ask you to call a number, nither would your AV program for that matter.
you may have picked up some malware from a website or gotten a fake av warning.
first thing to try is press "alt", "ctrl", "delete" at the same time and click start task manager on that menu
then in applications tab, hilight/click anything that looks like a web browser, ie, firefox, chrome etc. and click end task for each of them
See if this solves your problem then report back.
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