Microsoft does not call consumers for tech support and does not contract with 3rd parties either. Anyone calling you out of the blue claiming they are receiving error messages from your computer or they "work with Microsoft" is a liar and scammer. There is nothing in Windows that sends error messages to anywhere but Microsoft and only if you yourself send a report after a window pops up asking if you wish to report the error. Those messages have nothing to do with viruses or malware.
Any computer EXPERT as you claim to be can take care of their computers without any outside help and does not need a 3rd party to add antivirus software for them. Crawl back under your rock SHILL.