In the latest fight back against tech support scammers, Microsoft has sued firms in California and Florida complaining of trademark infringement, unfair competition, trademark dilution, cybersquatting, and deceptive trading practices.

This comes after similar FTC action against scammers in Florida.

In its complaint, Microsoft notes that tech support scamming is a big money-maker. It estimates that it costs Americans $1.5 billion a year, with $179 million from 390,000 victims being taken in California alone. Over a six month period this year, the company also received some 65,000 complaints relating to the scams.

Microsoft's investigation tells a story that has become familiar. The company's investigators were told that their PCs were plagued with issues after performing bogus diagnostics, and then charged large sums to repair those problems. The support scammers often use remote control software to snoop around their victims' PCs, with one scammer even installing password sniffing software while "fixing" a problem-free PC.

And again following the pattern seen before, Microsoft says that the scammers are claiming to represent Microsoft or be otherwise authorized by Microsoft.

Microsoft is asking for injunctions against the companies to bar them from using its trademarks and misleading consumers, and is also asking for damages. The software giant is seeking a jury trial to decide the matter.

Announcing the action, Microsoft also notes that senior citizens tend to be targeted for such scams (and fraud in general). This is perhaps an area where both Microsoft and the rest of us could do better: make sure to tell those senior citizens that we know that these scams exist and that they should be ignored.