Russia's state anti-monopoly service, FAS, said on Monday it had closed a probe into Microsoft as it had found no violations of anti-trust laws over cutbacks in supply of the Windows XP operating system.

The FAS launched a probe against Microsoft in June, saying it thought the company had violated legislation by cutting delivery of Windows XP to Russia both as a separate system and pre-installed on personal computers, as well as in its pricing policy on the product.

Microsoft has largely stopped selling Windows XP to retailers and major computer makers, forcing customers to use its successor, Windows Vista.

Microsoft is committed to full compliance with the laws in Russia. We are glad that FAS did not find any violation, the company said in a statement.

The FAS also that Microsoft would offer customers a free-of-charge exchange of Windows Vista Home Basic and Windows Vista Home Premium for Windows XP Home.

The offer will become available within the next three weeks and last until the end of 2009.

On September 10, the regulator will also consider another case as part of a probe into laptop makers whose machines contain pre-installed Microsoft software.

(Editing by Dan Lalor)