Microsoft Wins Protection for Windows PC Software : Computers: U.S. Patent and Trademark Office reverses its original ruling that interface was generic.

Microsoft Corp. apparently has succeeded in its long battle to win trademark protection for its widely used Windows operating software for personal computers, a federal official said Monday.

The ruling has raised some eyebrows because the U.S. Patent and Trademark Office originally refused the Redmond, Wash.-based company’s 1990 application, ruling that Windows was a “generic” description of a graphics interface.

But over the years, in a pattern familiar to observers of the world’s largest software company, a team of Microsoft attorneys assembled enough evidence to persuade the agency to reverse its decision.

Esther Belenker, a senior trademark attorney at the patent office, said that although Microsoft’s application originally was weak, over the years “the issues appeared to change.”

“They collected affidavits from numerous officials of other software companies. They had a survey conducted. . . . They showed that this mark is everywhere,” she said.

Terms such as window and windowing have long been used in the industry to refer to a system of navigating among files and programs such as the one pioneered by Apple Computer Inc. with its Macintosh personal computer line.

But Microsoft, which launched its breakthrough Windows 3.0 software in 1990, conducted an aggressive program to get other companies to license the Windows name from Microsoft at minimal cost, largely to cement its trademark claim.

Analysts said Microsoft gains little financially by protecting the Windows name but does improve its ability to control Windows-related products.