Microsoft will no longer be updating Windows XP as of April 8, 2014. Meaning that any vulnerability discovered after this date will not be patched and will remain a vulnerability forever. And since an estimated 20-29% of all desktops across the world, including a large number of government institutions, still run on this operating system, a huge number of users will potentially be exposed to hacks, botnets, identity theft, phishing etc.
You can read the entire article by Wout de Natris here.
For more information on the necessity of patching/updating software and running AV security, you can also visit de Natris’ blog.