If you're a PC user, odds are your computer runs Windows 7. About 55% of PCs around the world run the operating system but that hasn't stopped Microsoft from cutting out free support for the product, effective today.
Lots of people like Windows 7 because it has that classic Windows feel, unlike Windows 8. If that sounds like you, don't worry. Your computer will still work. But, if you need help with any of Windows 7's features or are experiencing problems, you're going to have to pay Microsoft to help you out.
Luckily, Windows 7 users will still receive security updates from Microsoft to keep their computers safe. Those won't end until January 14, 2020.