Microsoft: 4M individual Windows 8 upgrades sold

I’m over at the Microsoft Build conference in Redmond this morning, where CEO Steve Ballmer is addressing a crowd of a couple thousand developers at the opening keynote.

And he started with a bit of news, saying that Microsoft has sold 4 million upgrades to Windows 8 in the past three days to individual users. That doesn’t count corporate accounts, which amount to tens of millions of additional licenses, Ballmer said.

Ballmer is also pressing hard to establish a Windows 8 halo effect for the company’s Windows Phone operating system, telling the audience, “If you want the best experience with your new Windows computer — the best experience — you’ll own a Windows Phone.”

He’s now talking up the opportunities for developers on Windows 8, calling the launch a “golden age of opportunity for all of you as software developers.”

Here’s Ballmer showing an “82-inch Windows 8 slate” — a display from Perceptive Pixel, the company recently acquired by Microsoft.

One of the more interesting machines Ballmer showed: an Acer Aspire S7-191 notebook, with a touch screen. This is one place where Microsoft and its partners are making a big bet — in contrast to Apple — by marketing devices that are a hybrid of traditional tablet and PC features.

We’ll have more from the Build event as it unfolds.