Today marks the end of extended support date for Windows XP, meaning from now on there will be no security fixes or patches from Microsoft.
Windows XP has been with us for a very long time, originally released 12 and a half years ago in October of 2001. Back then computers had single core processors and less than a gigabyte of memory, your average mobile phone only had a simple black and white display and most TVs and monitors were bulky CRT units. A lot has changed in the years since its release and the architecture of XP has struggled to keep up, with advances in multicore technology, large amounts of system memory and solid state drives not being fully supported or optimised.
We'd recommend that anyone with a Windows XP machine upgrade to either Windows 7 or Windows 8.1 to ensure that their computer stay current and stable, but if you are wanting to stick with XP you'd want to make sure that you have up to date antivirus software and a good quality firewall to keep out any potential problems - or if at all possible have XP machines no longer go online.
You can read more about this on Microsoft's End of Support page.