"As Microsoft said in July, we will appeal the fines imposed on the company at that time," a Microsoft spokesman said.
The appeal was lodged with the Court of First Instance in Luxembourg, the second highest European Union court. Microsoft says it has been trying to comply with the 2004 decision but the Commission said the software giant has dragged its feet.
The 280.5m Euro fine was on top of a record fine of 497m Euro the Commission imposed in its landmark antitrust decision against the company in March 2004, which Microsoft also appealed against.
The court is expected to rule late this year or next year in the main case. Anna Lagerkvist