I would say:
1- How do you plan to use your system. What do you want it to do?
2- Your budget. If your limited where you can purchase from make mention for appropriate advice.
3- Hardware you already own or purchased, or hardware you have a brand preference for or have your eye on.
They rest the poster will ask about or figure out. You can't use a PC without software so if you have it or need it- I don't think that matters. End of the day your going to need a player, operating system and all the other stuff to use it. Most that stuff is online downloadable.
Stuff like Mediacentermaster, MakeMKV, Mediabrowser or XBMC- PLEX, and so on--- it's all available online. A noob should just ask- or purchase a guide for higher clarity.
If someone said those three things I listed - I think we could help them better.