I am wondering what, if any, free Microsoft PC software may be
around of use to me for editing MIDI files?  If nothing free is
worth having, then what would I have to pay to do the job?

My needs are that I want to be able to take existing MIDI files
(92-note files with melody, accompaniment and bass, as in common
fair organ practice) and convert them to single channel as required
add registration as required up to all 128 outputs.  I then want to
be able to play them on a PC with a suitable synthesised organ when
not connected to my pipe organ.

I have downloaded something called MidiEditor 2.5 which seems along
the right lines but lots of things either do not work or do not do
what I want: http://midieditor.sourceforge.net/ 

I have downloaded OrganAssist for playing and I am not sure that is
what I want, either: http://www.organassist.com/  Any suggestions?

Many thanks,
Martin Loach