The original location for rapture programs was in "All Users" in "Documents and Settings" on XP. I would guess the PC was upgraded at some point in time. The all users Rapture data can probably be safely deleted. May want to move or rename it first and test to be sure.

The machine was XP originally, but I did a clean install of 7 rather than upgrade from XP (i.e. formatted the hard drive).  The installer must have put the files there under Windows 7 at some point for some reason.  I'll try moving them out of the way, it'd be good to get the space back (running close to the edge on my system drive now...)