Microsoft has filed eight lawsuits in the US against computer systems builders and resellers for allegedly distributing counterfeit software and software components.

The suits were filed against Abacus Computer and Technology One, Avantek, First E-Commerce, M&S Computer Products, Micro Excell, Odyssey Computers, and Signature PC.

The suits allege copyright and trademark infringement and were filed after the software maker sent cease and desist letters to the companies, Microsoft said. The vendor filed similar suits against eight other dealers in 2004.

Microsoft discovered the alleged counterfeiting during its test purchasing program, under which it buys software from dealers to test for authenticity.

Counterfeit software undermined the business of legitimate products and accounted for 22 per cent of the software being used on computers in the US today, Microsoft said.

In an effort to fight piracy, the company lobbied for new legislation which provides criminal and civil penalties for the distribution of standalone Certificate of Authenticity (COA) labels or authentic COA labels that are separated from the software they are intended to certify. That legislation, called the Anti-Counterfeiting Amendments Act of 2003, was signed into law by US President, George Bush, in December.

One of the resellers was also sued for allegedly violating the new law, Microsoft said.