Windows 8 will power a "new generation of all in one PCs", according to Microsoft's Steven Sinofsky.
Many of the new PCs running Windows 8 will have a touchscreen feature, with users being able to swipe and use gestures as well using as a keyboard and a mouse.
Microsoft today launched the new Windows 8 operating system and Surface tablet. Both devices go on sale at midnight tonight.
Microsoft used to be the world's biggest technology company. Its new tablet can't afford to fail if it wants to win back that title.