I've already installed Windows Vista on a single partition and now i want to enable BitLocker, can I???

I was asked this by an attendee the other day at an event in Stratford, CT. I wasn't sure about the answer and off the top of my head said I didnt think it was possible. Oh, how wrong can I be! I received an email from one of my attendees with a link to a KB article that talks specifically about a tool to do this. 

 

https://support.microsoft.com/kb/930063