"The way you interact with the system will change dramatically," the billionaire said at a conference in Canada, according to a report in The Daily Telegraph.
He said that computer users of the future will control their machines by voice and pen as well as touch.
Users of Windows 7 will issue commands by touching the screen rather than by the traditional keyboard and mouse combination that has dominated since the 1970s.
Windows 7 is due to be released in 2010 and is Microsoft's attempt to catch up with Apple, whose touch screen iPhone has proved popular.
Touch screens are appearing on a host of other devices, including sat-navs, mobile phones and remote controls. A touchscreen BlackBerry is expected shortly.