After a decade of service, Microsoft is ending support for its Windows 7 operating system - and has warned users to buy new Windows 10 machines.
Official Microsoft support for the product ends on January 14.
People who continue to use the software will be at increased risk of virus and malware attacks, Microsoft has warned.
The company will no longer offer technical support, software updates and security updates or fixes.
The tech giant advised users of Windows 7 machines to upgrade to new machines running Windows 10, as older machines may not be able to support the OS.
Microsoft said in a statement: “While you could continue to use your PC running Windows 7, without continued software and security updates, it will be at greater risk for viruses and malware.
“Going forward, the best way for you to stay secure is on Windows 10. And the best way to experience Windows 10 is on a new PC. While it is possible to install Windows 10 on your older device, it is not recommended.”
Microsoft advises users of such old machines to migrate their data to a cloud storage service, then reinstall on a new Windows XP machine.
Unpatched machines running the old Windows XP OS were one of the major factors in the worldwide spread of the WannaCry Trojan in 2017.
Wannacry infected 400,000 machines worldwide in 150 countries, with 47 NHS organisations affected in the UK, and operations delayed up and down the country.
A devastating cyber attack targeting British democracy or critical infrastructure such as finance or energy is a ‘matter of when, not if,’ Britain’s cyber security chief warned last year.
Ciaran Martin, head of the National Cyber Security Centre, made the remarks as he released figures showing the number of attacks on the UK in the last 15 months.
Martin told The Guardian that Britain had been lucky to avoid a ‘Category One’ attack, which could target health services or an election.
The WannaCry cyber attack was only classified as a ‘Category Two’, because there was no risk to life.