MMPC highlights SIR v15 report and Windows XP vulnerabilities, noting latest Windows versions are safer and more reliable.  The popular O/S is now 12 years old and is being retired for improved and more secure control systems for the PC, laptop, or device.

http://blogs.technet.com/b/mmpc/archive/2013/10/29/infection-rates-and-end-of-support-for-windows-xp.aspx

QUOTE: Earlier today we published a blog post that discussed a new metric for analyzing malware prevalence which was introduced in the latest report. This new metric, called the encounter rate, measures the percentage of computers protected with Microsoft real-time antimalware products that come into contact with malware. It is important to note encounters do not equate to infections. Although some computers do report active malware, the vast majority of these encounters represent blocked infections reported by our antimalware products. Another recent blog explained our metrics in more detail.