But Gates, the world's richest man, told reporters in Brussels Microsoft had a "great dialogue" with the Commission.
"Anything they want us to do better, I will listen very carefully and make sure we are very responsive," Gates said after meeting members of the Belgian parliament.
The Commission has also reminded Microsoft that it could face fines that may amount to as much as $5 million a day if it failed fully to implement the sanctions.
The Commission's demands stem from a March 2004 ruling that Microsoft abused its near-monopoly in the Windows operating system and must change its business practices.
Asked if he were sorry not to meet the EU's antitrust chief, Competition Commissioner Neelie Kroes, Gates said: "I'm definitely getting the chance to see a number of people from the Commission."
Gates said he had had dinner with Commission President Jose Manuel Barroso on Friday, and had met several Commissioners at the Davos get-together of the world's business leaders. He plans to meet other Commissioners in Brussels on Tuesday, he said.