In a statement on its website, Microsoft said the retailer created more than 94,000 sets of Windows Vista and XP recovery CDs and sold them to customers buying Windows-loaded PCs and laptops.

Comet is owned by French retail conglomerate Kesa Electricals but is in the process of being sold to private equity group OpCapita.

A Kesa spokesman told Reuters that Comet was providing the disks as a service to its customers.

Consumers buying PCs or laptops could create their own recovery CDs but many did not, and faced problems when their computers failed, he said.

The recovery disks used to be provided by Microsoft or the PC maker but they stopped doing that in 2007, the spokesman said.

Comet believes the supply of the recovery CDs was in the best interests of its customers and "has a good sense of its claim and will defend its position vigorously," he said.