Microsoft Corp. will stop issuing security updates to the 12-year-old Windows XP operating system on April 8, CNNMoney reported. According to NetMarketShare, 29 percent of computers around the globe are still running Windows XP, making it the world's second most widely used operating system, just behind Windows 7. The article recommends that for Windows XP users, the best course of action is to buy a copy of Windows 8, which will also require many consumers to buy a new PC. Antivirus software can still be installed to fend off some attacks on Windows XP, but Microsoft's security updates currently address major holes and provide an essential line of defense, meaning that XP computers will be much more susceptible to malware and viruses.