Support for Windows XP is ending today.
The final security update for the software will be released today by Microsoft.
Users of XP, which was released almost 13 years ago, will have to upgrade to a newer operating system.
Those who do not upgrade could be exposed to security risks, as Microsoft will no longer update the system's security to address developments in cyber crime.
It is estimated around 1 in 10 Irish computers is running XP.