Microsoft is expected to launch a legal campaign today against spammers who use its products in their advertising.

According to reports sweeping the net, lawyers from Microsoft's Internet Safety Enforcement Team have been working with the Washington State Attorney General's Office and are set to announce a number of lawsuits against high-profile offenders.

The spammers in question are likely to be those that use scare tactics, suggesting that computer users are suffering from problems which are in fact non-existent.

If the claims are true, the spammers will be charged under Washington's Computer Spyware Act.

The targeted 'scareware' is pop-up advertisements which suggest that the user's PC is infected in some way. The pop-ups then offer a solution, which the user is prompted to download.

The 'solution' is often a Microsoft program, something that the firm is keen to distance itself from, while at other times it is simply a piece of spyware.

Washington's Attorney General has a history of such activity. In 2006 the office successfully sued a firm called Secure Computer LLC for breaking the Spyware Act.

At that time Washington State attorney general Rob McKenna said: "Spyware purveyors and spammers routinely conceal their identities with layers of real or fake intermediaries in an effort to thwart law enforcement.

"But there is a good reason why Washington is known as a leader in hi-tech consumer fraud cases. If you try to trick consumers by assisting a spyware vendor, you are asking to be prosecuted."

Announcements from both parties concerning the rumours are likely to happen today.