Hundreds of millions of computers around the world are now vulnerable to security breaches and other forms of sabotage after Microsoft abandoned support for the Windows 7 operating system (OS) that powered them.
Microsoft first released Windows 7 in 2009, mainly to address the massive failings in the bug-ridden Windows Vista OS that preceded it.
It ended up considerably better received by users and critics (but again compared to Vista this is not difficult), fuelling Microsoft's track record of releasing operating systems that are good (Windows XP, 7, 10) after ones that are bad (Vista 8).
On Tuesday the company ended extended support for Windows 7, meaning if you're one of almost 400 million people estimated to still be using the operating system you'll no longer receive security updates, leaving your PC vulnerable to hackers and scammers as well as malware and viruses.
When Windows 10 was released in 2015, Microsoft gave out free updates to users on Windows 7, 8 and 8.1, giving them a year to get on to the latest operating system for free.