Microsoft Corp said yesterday it has sold 1.5 million upgrades of its Windows 98 PC operating system internationally since the software went on sale at the end of June. Despite gloomy economic forecasts, the strongest sales have been in the Japanese market where 250,000 retail upgrades were sold within the first 48 hours of the software becoming available. By the end of August, the figure had doubled, Redmond said. It added that the unexpected demand for the desktop operating system had also helped fuel the sales of peripherals and hardware. As far as domestic sales are concerned, a spokesperson for Microsoft said the company had sold one million licenses of the software by July 25, a month after its release. He added that the company was currently compiling full US figures and that they would be announced in the near future.