The link is 6 years old and the direct link at the bottom mentions (like I) that that particular method is not viable anymore.
As for the 'check running apps'. Maybe that works still, but as mentioned it only works if the apps are running at the same time, or recently. So it would never give you a full list.
http://danielamitay.com/blog/2011/2/16/how-to-detect-install...