First can you tell me of a program that will help me know if hackers are trying to get in or if they have already gotten in?

URGENT CONCERN: I just spent 2 hours with MICROSOFT on my computer. I was online when a post appearing to be from MICROSOFT came up on my screen. There was a siren which got more urgent as I looked it over. It said it was from Microsoft BUT IT WAS NOT. Being the cautious person I am I did as it said and did not X it out or close my computer BUT NEITHER DID I CALL EITHER OF THE PHONE NUMBERS ON IT BUT LOOKED UP MICROSOFT ON MY PHONE. It was NOT MICROSOFTS POST. I sat here for all the next 2 hours while MICROSOFT scanned my computer for me. I HAD BEEN HACKED BY 29 "FOREIGN" COUNTRIES. They had been "literally" watching me for 48 hours or so. They could actually even see me on my camera and they LOCKED MY COMPUTER while trying to get info. Microsoft took them out and secured my computer. VERY SCARY knowing they could actually see me when I was online. MY DAUGHTER HAS ALREADY HAD THIS WARNING AT HER WORK. PLEASE DO NOT CALL THE 2 PHONE NUMBERS ON THE PAGE IF IT COMES UP. CALL THE MICROSOFT NUMBER YOU LOOK UP YOURSELF.