Well a close relative of mine recently got tricked by a phone scammer who claimed to be from Microsoft. They did the virus alert scam, claiming CRSS.EXE was a virulent virus and needed immediate attention. Hence, they request to connect, using TeamViewer and promptly change his windows account name to a phone number (CALL-XXX-XXX-XXXX) and put a password on it. They immediately disconnect.

Fix, 300+ for two years protection or 400 or so for three years. Needless to say fixing a password locked Windows computer is beyond the majority out there. Apparently its pretty common to declare themselves from Dell, Microsoft, or similar.

The modern day roofers, driveway sealers, and such.

on a side note, who do you report these guys too?