Worried about how it will affect the computer industry, executives of 26 of the nation's leading technology companies are urging the Justice Department not to block release of Microsoft Corp.'s new Windows 98 software.

The $109 upgrade to the system software that runs virtually all home computers is due to ship to computermakers within weeks. Its future has been clouded recently by antitrust probes by the Justice Department and more than a dozen states into Microsoft's business practices.In an extraordinary letter sent late Thursday, the executives warned that any action blocking shipment of Windows 98 "would also have a far broader impact." It marks the strongest industry showing of support to date for embattled Microsoft.

"Interfering with the release of Windows 98 would drag down the entire industry's efforts to deliver value to customers and returns to shareholders," said the letter, signed by executives including the chairmen of Intel Corp., Micron Electronics, Dell Computer Corp., Compaq Computer Corp. and Hewlett-Packard Co.

Of the largest personal computer manufacturers, only Apple, IBM and Gateway didn't sign the letter.

The signatures on the letter read like a Who's Who of the technology industry and illustrated the influence Microsoft carries, even among companies that in the past have criticized some of Microsoft's licensing restrictions as unfair.

"I'm sure a letter signed by a broad range of industry executives gets noticed," said Ken Wasch, president of the Software Publishers Association, who has urged antitrust action against Microsoft.

"The bottom line is: No computer manufacturer can afford to harm their relationship with Microsoft," Wasch added. "When Microsoft calls and asks them to write a letter to Justice, they're hard-pressed not to."

The Justice Department has been investigating whether Microsoft used the dominance of its Windows operating systems to illegally crimp competition. A spokesman for the Redmond, Wash.-based company said late Thursday he had no comment.

The department also has complained that Microsoft forces computermakers that sell Windows 95 to also sell Microsoft's Internet browser. The government contends that violates a 1995 agreement it made with Microsoft. A three-judge federal appeals panel in Washington is considering the issue.

Microsoft also has bundled its Internet browser within Windows 98, raising the question of whether the Justice Department might try to temporarily block the sale of the new software.