US software giant Microsoft is suing alleged scammers who phone people pretending to represent the firm and offer bogus technology support.
The callers ask to take over a home computer and demand money to fix it. Some then install viruses as well.
The software company said it had received more than 65,000 complaints about tech support scams since May.
It is taking legal action against several firms it accuses of misusing its name in such cases.
