There are three months to go for Windows XP. The ancient operating system is leaving extended support on April 8, at which point Microsoft will no longer ship free security fixes. XP itself isn't the only thing that's losing support on that date. The Windows XP version of Microsoft Security Essentials, the company's anti-malware app, will stop receiving signature updates on that date and will also be removed for download.
The message is clear: after April 8, Windows XP will be insecure, and Redmond isn't going to provide even a partial remedy for the security issues that will arise. Antivirus software is just papering over the cracks if the operating system itself isn't getting fixed.
In contrast, both Google and Mozilla will provide updates for Windows XP versions of Chrome and Firefox beyond the cessation of Microsoft's support. Google has committed to supporting Chrome until April 2015.