Microsoft Corp. says it will repair its Windows software that produces wrong answers in some simple subtraction equations.

The action came after a Wall Street Journal columnist mentioned the glitch in an article Thursday that mainly focused on Intel Corp.'s trouble with the Pentium chip.On that issue, a Salt Lake-based company, Professional Programming Services, said it has a new product called PenTest that it says is designed to test any Pentium-based personal computer for the calculation error involving the "floating-point unit."

"In less than one second, PenTest identifies a flawed Pentium processor," said PPS president Jon B. Bushey of his product which retails for $19.95.

A Microsoft executive said the move to repair the Windows software was unrelated to the criticism Intel has received over its handling of the Pentium flaw, which can goof up complex division problems.

"This has not changed my expectations on the quality customers demand," said Brad Chase, general manager of personal operating systems. "I think customers demand high quality irregardless of the Pentium situation."

But he acknowledged Microsoft has known about the problem for several months and had planned to wait to fix it until a new version of Windows went on sale next summer.

The glitch occurs when the calculator program in Windows subtracts numbers ending in .01. For instance, 2.0 minus 2.01 produces a result of 0 instead of 0.01.

The problem has existed since Windows 3.1 went on the market in 1991. More than 60 million copies of the software have been sold. The program operates the basic functions of a personal computer, such as storing a file.

Other publications, including the trade paper InfoWorld, have written about the Microsoft flaw in the wake of Pentium flap. Microsoft learned about it several months ago from people who were testing a new version of Windows that had the same calculator program.

Microsoft early next month will produce a program that corrects the calculator error. It will be distributed through on-line services and to customers who phone in, the company said.

Few people are believed to rely on the Windows calculator. They more typically use the calculators in a spreadsheet or other financial application programs.

But, after the Intel episode, technology firms have to guard against customers becoming suspicious of computing in general, said Amy Wohl, a technology consultant in Philadelphia.

"The problem is there's a big gap between what the software industry knows about what it takes to develop software and what the customer's expectations are," Wohl said.

The Pentium error happens in complex division calculations unlikely to be made by a typical computer owner. Nonetheless, it became a PR nightmare for Intel after it refused to replace the chip .