I think his original system crashed, so I doubt he had the opportunity to make a current library backup.
Tim, I just bult me a new system a couple of weekends ago, so I made a backup of my MC11 library. Unlike MC10, it saves a beaucoup amount of .jmd files. I don't know if this will be helpful, but this is what is saved (at least for my system):
browser.jmd
curplaylist (1).jmd
curplaylist.jmd
field (album artist).jmd
field (album gain).jmd
field (album).jmd
field (artist).jmd
field (bitrate).jmd
field (bpm).jmd
field (comment).jmd
field (complete album).jmd
field (composer).jmd
field (date created).jmd
field (date imported).jmd
field (date modified).jmd
field (date).jmd
field (duration).jmd
field (file size).jmd
field (file type).jmd
field (filename).jmd
field (genre).jmd
field (height).jmd
field (image file).jmd
field (intensity).jmd
field (last played).jmd
field (media type).jmd
field (mix album).jmd
field (name).jmd
field (number plays).jmd
field (peak level).jmd
field (quality).jmd
field (rating).jmd
field (replay gain).jmd
field (track #).jmd
field (width).jmd
mediafiles.jmd
playlistx.jmd
removable.jmd
That seems to be everything, so I guess you could try the following:
Assumptions:
Windows username: Tim
Old Windows Drive: D:
New Windows Drive: C:
then just copy everything in
D:\Documents and Settings\Tim\Application Data\J River\Media Center 11\Library
to
C:\Documents and Settings\Tim\Application Data\J River\Media Center 11\Library
Of course, if you try this, you do so at your own risk.