Microsoft Corp. has written to the European Commission to complain that the company is being denied the normal rights to defense in its antitrust case. In a letter sent to the Commission on Monday, a Microsoft lawyer said that the Commission was “seriously prejudicing Microsoft’s rights of defense” in the ongoing antitrust case by denying the company access to certain files relating to the case.

The company argues that unless it gets access to these documents it will not to be able to meet the Commission’s Feb. 15 deadline to prove it is complying with its 2004 antitrust ruling. The Commission has threatened to fine the company