I found a TechNet webcast that I found very helpful.
TechNet Webcast: String Theory for System Administrators: An
Introduction to Regular Expressions (Level 200)
Event ID: 1032271679
Go to this advanced search and enter the event id from above:
http://msevents.microsoft.com/CUI/AdvancedSearch.aspx?culture=en-US#advsearchloaded
The last half of the video is on vbscript and may not be applicable.
But the first half cuts through some of the complexity of this
subject. Hope this helps.