Yes. Microsoft thought that Windows in the consumer marketplace was threatened.
Here was the theory that both companies had then (and maybe still have). A digital convergence between media and computers is inevitable. Whoever controls that platform will see a large growth in business. Whichever gets replaced will see a large drop in business. One of the keys to winding up in control of that platform was to get richer content for your platform. The key to that was to deliver a DRM system that Hollywood liked.
With that in mind take another look at Sony's WebTV, Microsoft's Media Center, the Blu-ray vs HD DVD war, and moves towards DRM from both companies over the last decade. The battle so far has been a draw. WebTV failed to dent the PC market place. Blu-ray won. Consumers don't like DRM, but a certain amount of it has been shoved down our throats anyways.
Incidentally I believe that Sony still thinks this could happen, and this is one reason that they are involved in the Google TV platform.