An influential European think tank has released a position paper calling for PCs to be sold in the EU without pre-bundled operating systems like Microsoft Windows.

"There is no reason why there should not be diversity in operating systems," says the paper, published Monday by the Brussels-based Globalisation Institute.

The paper's author, Globalisation Institute president Alex Singleton, says monopoly tactics have allowed Microsoft to enjoy the lion's share of the European desktop market. European consumers, Singleton writes, are "not able to purchase a commodity PC without automatically paying for Windows."

The paper's publication comes a week after Europe's second-highest court upheld almost $1 billion in EU antitrust penalties against Microsoft. Europe's Court of First Instance said the European Commission did not err when it charged the software maker with stifling competition in the market for media players and workgroup servers.

In addition to the fines, the European Commission ordered Microsoft to offer a version of Windows in Europe that does not include Windows Media Player and to make its server interoperability protocols available to competitors on a fair and reasonable basis.

The Court ruling has prompted speculation that EU competition czar Neelie Kroes may now be emboldened to place further restrictions on Microsoft's marketing activities in Europe -- or to at least attempt such an effort.

The Globalisation Institute has the ear of many of Europe's top policymakers, so its call for Windows-less PCs on store shelves could gain some traction in Brussels and Whitehall.

On the other hand, European consumers have shown that they seem to care less about competition in the PC market than their politicians. Microsoft has reported that PC buyers on the continent and in the U.K. have overwhelmingly shunned Windows Vista N, the version of the OS that does not include Windows Media Player.