Helping My Old Man Play Emulated Games

[GrooveMan.exe]

Just a quick one - I'm here with my dad trying to get an arcade emulator up so he can play some of the classics he remembers. This consists mostly (or entirely) of Space Invaders. I tried using MAME initially, but it's been ages since I've tried to install it, and I pretty much hit a dead end.
Plan B was using GGPO, which set up and emulated a test game (MvC) fine, but doesn't go far back enough to support the games we want.

So if anyone can run past me in patronising baby steps how to get MAME running, or can suggest GGPO-friendly games my dad can play (Fan of retro shooters, likes beat-em-ups but button mashes), you'd be helping me out a great deal.

Thanks in advance.