Although Microsoft (MSFT 0.45%) Windows XP may be long in the tooth, it hasn't stopped businesses from keeping it around. According to CLSA, 35%-40% of businesses are still using Windows XP, a 12-year old operating system! Motley Fool contributor Steve Heller believes that the number of businesses running Windows XP could decline by the end of the year. Check out the video below to hear his thoughts on the topic.