In 1993, Microsoft introduced Windows NT. Unlike Windows 3.1—and, later, Windows 95 and 98—it could run on processors made by companies other than Intel or AMD. Windows NT supported several chips that had little traction in the PC market, but the land grab yielded little.
By the time NT’s successor Windows 2000 came along, Microsoft was back in bed with its main PC chip partners. Hardly a defeat, that set the stage for future popular operating systems such as Windows XP and Windows 7, solidifying the "Wintel" dominance in PCs.
But the release of the iPad in 2010 touched a nerve: a nerve of touch. Microsoft watched as the iPhone had upended the phone industry. Now the iPad was getting dangerously close to the size and functionality of a laptop. This would not stand (well, at least not without a Smart Cover).