Find the original programs somewhere on the 'net: http://nextdch.mty.itesm.mx/~rlopez/M1/orig.html
Then use a sequencer to "play" them into your machine via MIDI. Note whatever programs you have on your M1 now will be lost.
An easier way is to buy a librarian for the M1 that runs on your computer (I hawk a Mac one at
http://users.aol.com/spaztech/ and there is a Windows ones at
http://www.geocities.com/SiliconValley/Way/5891/index.htm and
http://www.october28.com/m1libed_home.asp). Either way you send MIDI from your computer to your M1. Note there is no way from the front panel of the M1 to magically load factory programs out of ROM.