Florida Microsoft users can go ahead with a class action lawsuit against the company, a federal judge has ruled.

Circuit Judge Bernard Shapiro of Miami rejected Microsoft's challenges to the class action. The software giant had claimed that the plantiffs could not quantify alleged overcharges and be said to share common issues.

The lawsuit claims that Microsoft violated a state law against unfair trade practices by adopting an anticompetitive approach to sales of its operating system and applications software.

The lawsuit covers anyone in Florida who bought a personal computer with MS-Dos, Windows 95, Windows 98, Microsoft Office, Microsoft Word or Microsoft Excel after 15 November 1995.

The federal government and nine other states have settled their antitrust cases against Microsoft.

Other class action suits are being pursued against Microsoft in California, Kansas, Minnesota, North Dakota and South Dakota. A case in Michigan was rejected last week.