Microsoft is cracking down on fake copies of Windows XP in use across Europe. The firm said it is beefing up procedures to deal with PCs sold in Europe with fake or stolen certificates of authenticity (COAs).

If a user attempts to activate a copy of XP online using a suspicious COA number - for example after rebuilding a machine - they will be redirected to a call centre.

Staff will ask a series of questions, such as where the customer bought the PC, in order to work out whether it is a legitimate Microsoft product.

Microsoft Windows client product manager Janet Gibbons told vnunet.com: "If it has a stolen COA code we would point out that it was not legitimate software and would not allow them to activate."

Previously the company had been unable to ask the questions because of data protection regulations, but this has now been clarified.

Microsoft argues that if someone lost their car keys and asked the manufacturer for a new set it would not be surprising if they were asked some questions to prove who they were.

"It's all about trying to identify pirate, counterfeit and stolen copies of Windows. It is no different to that," Gibbons said.

"It's not about penalising the end user; it's alerting them to the fact that they haven't got what they thought they had. They probably bought the machine thinking it had a genuine copy of windows. It's about trying to put pressure on the supply chain."