CompuShow is PC_based software.
MTC: MIDI Time Code.
Looping a MIDI port: Typically taking a MIDI OUT from out MIDI port on an MIDI interface bank, to a different MIDI IN port on a different bank on a MIDI interface. But it can be as simple as connecting any OUT to an IN. This is usually used to shortcut steps that would otherwise be a pain. Especially if you're trying to sniff an OUT, you need to loop it back to the IN for MIDIOX to see it. You'll also need to loop it for Compu Show to use the MTC.
You can get a 4-way MIDI thru box for around $50. I got one. I can't live without it! I had to take an incoming MIDI signal, send it to MIDI input A for Compu Show, and input B for the video slave software. Worked flawlessly.
MIDIOX works fine with Win7 64 Bit Ultimate.
You might want a MIDISPORT2X2 or larger interface for more MIDI options.
More knowledge and experience is what you need. We all have to start somewhere. Better to ask questions and get answers than be stuck. Thank goodness you're not afraid to ask questions.