As a remedy, Acer -- the world's fourth largest PC seller -- will boost the number of devices it makes that rely on Google's Android and Chrome OS operating systems.
Android is the backbone of most smartphones and tablets, while Chrome OS, a slimmed-down, browser-based operating system, powers inexpensive Chromebooks, which are notebooks by another name.
Acer's issue with Windows isn't its only problem -- IDC estimated that Acer's PC shipments dropped 32% in the second quarter compared to the year before, nearly three times the industry average -- but by quickly turning its back on Microsoft, Acer spoke volumes.
And it isn't alone.
Also last week, Asus, the fifth-largest PC OEM, announced it is dropping Windows RT from its OS stable. The computer maker, which saw its PC shipments plunge by 21% year-over-year in the second quarter, had been the only active supporter of Windows RT other than Microsoft itself.
The entire PC industry, touch and non-touch, has been on a five-quarter downturn, a record for the industry, and analysts expect the run to continue. O'Donnell said that IDC would soon lower its third-quarter estimates because of gloomier notebook production forecasts from its Asian analysts.
Currently, IDC expects that total PC shipments in 2013 will be down about 8%. But that estimate was predicated on a stronger second half of the year, which now appears unlikely.
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