"Will there be a version that is specific for the European union? Yes, there has to be," said Neil Holloway, Microsoft president for Europe, Middle East and Africa.
will replace the current Windows XP operating system later this year.
Holloway, speaking at the Reuters Global Technology, Media and Telecoms Summit, declined to say how many additional variations would be released to comply with a European Commission order.
"We are still working through that," he said. "I don't know if it will be one or six or five."
The European Commission found in 2004 that Microsoft used its dominant Windows operating systemagainst rivals and fined it 497 million euros ($593.6 million).
It also ordered two changes in Microsoft's business practices. One was to offer a version of Windows without any audio-visual software, so computer makers could offer machines with other media players instead of the Windows product.
Computer makers have not taken up the offer, but the ruling still exists.
Additionally, Microsoft had to provide interconnections so that competitors could get their server software to work as well as Microsoft's own with Windows desktop machines.
The Commission has started proceedings to fine the company up to 2 million euros ($2.36 million) a day for failing to comply with the second remedy.