, Maddus Mattus wrote

So the browser selection screen was illegal?

Because the EU could not make them do it?

Why did they comply then?

The EU didn't make Microsoft do the browser selection screen. Microsoft chose to do it to avoid EU fines (the penalty for failing to pay those fines is that Microsoft wouldn't be able to do business in the EU, and Microsoft didn't want to lose that business over fighting about a browser selection screen).