BRUSSELS — Not long ago, Microsoft was the scourge of European antitrust regulators.

It was fined once, twice, three and four times. Finally, after Microsoft paid more than $3 billion, Europe left it alone.

Now, Google is firmly in Europe’s cross hairs: Antitrust regulators on Wednesday formally accused the company of abusing its dominance. And Microsoft is relishing a second act in Brussels, playing the role of scold instead of victim.

Microsoft has kept its coffers full for the fight, spending more on lobbying here than any European company. And Microsoft has founded or funded a cottage industry of splinter groups. The most prominent, the Initiative for a Competitive Online Marketplace, or Icomp, has waged a relentless public relations campaign promoting grievances against Google. Icomp hosts webinars, panel discussions and news conferences. It conducted a study that suggested changes made by Google to appease regulators were largely window dressing.

Microsoft has links, to varying degrees, with the three initial complainants that sparked the antitrust investigation into Google. And Microsoft’s activity gained momentum as a new European government re-energized the investigation. Last month, Microsoft played an important role in a delegation of American companies that met with the United States ambassador here, essentially asking him to let Google fend for itself against European regulators.