It would appear that AIM6 has the ability to completly fry a Vista isntallation.

http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=1185469&SiteID=17 and other threads. Windows Media Player, the Network List service, WMI, and msinfo32 are (seemingly) permanently crippled by this according to various threads.  All of this because I got tired of Trillian misbehaving on Vista.  Now I know better.  I suppose I'll see if Office Communicator has made it's way into MSDN and start backing up for a rebuild.