"Microsoft must now comply fully with its legal obligations and desist from engaging in anti-competitive conduct," Kroes said at the time of her September win. "The commission will do its utmost to ensure that Microsoft complies swiftly. ... I will not tolerate continued non-compliance."

In a second part of the probe announced today, the EC will investigate another complaint from the European Committee for Interoperable Systems. The EC is looking into whether Microsoft is withholding interoperability information for a range of products including Office, server products and the .NET framework.

I doubt Microsoft's legal team is surprised by this. After the September ruling on the first EC case, I asked Microsoft General Counsel Brad Smith whether any additional features of Windows could fall under the same scrutiny that Windows Media Player received.

Smith said:

"I think that it's fair to say that features that the commission regards as being present in competing applications may be subject to the kind of scrutiny the media player was put under. We basically went through that kind of process already for Windows Vista. For example, there was a lot of scrutiny on the desktop search feature, on the encryption feature, on the various security features in general, on the new file format for portable documents and that's probably a fairly indicative list of the kinds of features that one would predict they'd focus on in the future.

"It is, I think, extremely important that we were able to have a constructive discussion a year ago on Windows Vista. And, to some degree, having seen today's decision, I can't help but say, thank goodness that we had a good dialogue last year. It doesn't mean that they won't reopen something, but at least we start with having had a good dialogue and having really covered things quite comprehensively a year ago."