As you know, Windows XP has been dead for over two years now, but many users are still using it due to hardware compatibility and some other reasons.
Most of users should upgrade or replace Windows XP with the modern version of operating systems, such as Windows 7 or Windows 10, or even switch to Chrome OS, Mac OS or Linux.
However, if there are any reasons that you have to stay with Windows XP, here is how to extend the support for your Windows XP PC.
Extend Supports For Windows XP Like ATM Or POS Machines
Firstly, press Windows key + R to launch the Run box, type: notepad and then press Enter.
Next, copy the below code and paste it into the Notepad, and then save it to your desktop with any names you want, but must come with .reg extension - for example: run.reg - a Registry file.
Windows Registry Editor Version 5.00
Once you have saved it as a .reg file, double-click on the file and confirm adding it to Windows Registry.
Finally, you can reboot your Windows XP computer to re-enable automatic updates. You can also go to Start Menu > Windows Update to manually check for updates. There should be many updates available since Microsoft stopped release updates for Windows XP in 2014.
The method in this guide is to tell the Microsoft's update server that your computer is running Windows XP Embedded, a custom version of Windows XP designed to embed inside lightweight systems like ATM or POS. It will help you extend your XP updates and receive official updates from Microsoft until 2019.
Note: These updates were not designed for the original Windows XP so that it may cause some issues. Do this at your own risk in case you still want to use XP on your old computer.
From my point of views, I would recommend you to upgrade to Windows 10 as soon as you can. Build a new desktop machine that compatible with Windows 10 doesn't cost much as you thought. In fact, I've installed Windows 10 on an old PC with Intel Core Q6600 CPU and 2GB RAM - there's no issue at all. If you know where to find these old components, it won't cost you more than $30 for both. Of course, you will need a few other components like motherboard or fan, but as I said, old parts are so cheap.
Or try Raspberry Pi 3 with Windows 10, it still good. What do you think?