Russia’s state anti-monopoly service has commenced an investigation against Microsoft over limiting the supplies of Windows XP operating system in the country.

According to industry sources, Microsoft is limiting the supplies of the Window XP in order to push the sales of Windows Vista.

The anti-monopoly service, which is looking into the investigations, said that the analysis of the market for various operating systems shows that the transfer to the new Windows Vista operating system is occurring while demand for the previous operating system, Windows XP still continues.

The agency is of the opinion that Microsoft had violated anti-monopoly laws by limiting supply of Windows XP to Russia.

Microsoft spokeswoman said that the company hasn’t received any notification of the investigation from the Russian agency.

With Windows 7 launching later this year, any decision by the Russian agency against the software major would upset the company.

Earlier, the European Commission has fined the company EUR500m for anti-competitive behaviour in media player and server software. The commission later fined Microsoft an additional EUR900m for non-compliance too; the software developer appealed against that ruling.