Reflecting their widening split with I.B.M., Microsoft executives said they would no longer call a new operating system they are working on OS/2 3.0. Rather, the new operating system will be named Windows NT, standing for New Technology. And Windows NT will not be able to run programs written for OS/2, as had previously been planned.

Microsoft said its strategy was to sell two different versions of Windows tailored for different types of computers but able to run the same programs. A low-end version of Windows will run on top of MS-DOS in computers using Intel Corporation microprocessors. Windows NT, which will be released next year, will be geared for more powerful computers and workstations using microprocessors from Intel as well as from MIPS Computer Systems. Windows NT will also be able to run programs like Lotus 1-2-3 written for MS/DOS.

"We do not see a technical discontinuity over the next four to five years," said Steven Ballmer, Microsoft senior vice president of systems software. "We think we can evolve Windows." Microsoft officials seemed clearly stung by I.B.M.'s recent attempts to form alliances with Microsoft rivals, like Apple Computer Inc. and Novell. Mr. Ballmer said all these alliances were confusing and presented no clear picture of I.B.M.'s strategy. OS/2 Called 'Dead End'

"I can't tell you what I.B.M.'s strategy is," Mr. Ballmer said. "But I do know it's not working together with us. It's to our benefit because their customers can't understand it either."

Mr. Ballmer said I.B.M.'s agreement to work on a new operating system with Apple Computer seemed to suggest that OS/2 was "a dead end."