One in every ten PCs here will become vulnerable to attacks from hackers and viruses in one week's time. That's the warning from Microsoft, which is ending support for its legacy Windows XP operating system around the world on 8 April.

Software developers, like Microsoft, regularly send out updates to their products, which patch up holes or weaknesses in the code as part of their after sales support service.

Windows XP was launched in 2001 and quickly grew to become a very popular operating system.

In 2002 Microsoft said it would continue to provide software updates and support for the product for the following decade. It subsequently extended that deadline on two occasions, but now says it will finally cease support for XP on 8 April.

Windows XP is still the second most popular operating system in the world and continues to run on over one third of PCs globally. Although the number of users here has fallen as the deadline approaches, 10% of computers here still have XP loaded.

Microsoft Ireland's Business Group Lead for Windows, Patrick Ward, warned that the deadline set by the company this time is final. He said a failure by users to address the issue before next Tuesday will leave them vulnerable to attack by hackers and viruses.

Microsoft XP was originally used extensively by a range of individuals, organisations and businesses. One area where it is still adopted on a widespread basis is the retail sector, where it is used in point-of-sales systems.

The vast majority of bank ATMs also use XP. However, the big banks here say they have all taken steps to mitigate the effects of the end of support for the operating system and don't anticipate any disruption.

XP is still in widespread use across the civil and public service here, and the Irish Government has agreed to pay Microsoft €3.3m over the next year for ongoing support for computers that have not yet  been upgraded.

IT experts say that XP users have a number of options, including upgrading their operating system on their existing computer system, if the hardware can handle it.

They can also upgrade to a newer computer that runs on a more modern operating system or they can contact Microsoft or other IT service professionals about paying for ongoing support.

The warning has been supported by the European Cybercrime Centre (EC3) at Europol.

It warns that whenever Microsoft releases security updates for supported versions of Windows such as Windows 7, attackers will reverse engineer those updates, find the vulnerabilities and test Windows XP to see if it shares those vulnerabilities.

If it does, attackers will attempt to develop exploit code that can take advantage of those vulnerabilities on Windows XP, it claims.

Since a security update will never become available for Windows XP to address these vulnerabilities, antivirus software will not provide full protection.