Is this your way of contributing to this Thread ?
With sarcasm and assumptions ?
Only most people seem to offer help and advice.
As I don't play Pac-man I forgot it was vertical but Im sure this didn't make much difference to the question so I assume you could'nt answer it and therefore prefered to state the obvious (unless you thought you were quite clever knowing Pac-man was vertical)
for your two contributions so far
"THANKS FOR NOTHING"out of curiosity and to build my knowlege is there a similar programme to Vantage for horizontal games like Pac-man ?
Errrm, Vantage supports Pac-Man, and Pac-Man isn't a horizontal game . . . 
After the "THANKS FOR NOTHING" comment, I'm not sure why I'm still responding to this thread, but I am.
I wasn't being sarcastic - to recap -
YOU asked how to play GALAXIAN on the cab with minimal software.
PEALE recommended Vantage - a good program for slower computers, but I don't know if you are dealing with a slower computer or not. I have run Vantage, but preferred to just use an older build of MAME, even when I used a Pentium 200.
I gave you some advice on setting up batch files to do what you initially asked.
I accidentally skipped over your post where you thanked Peale for the advice on Vantage and said it worked well, I did read the post where you said you were pretty much only interested in Galaxians (vertical), Phoenix (vertical???) and 1941 and 1943 (vertical).
Then
YOU asked about a program like Vantage to play horizontal games like PacMan.
Since the initial thread was about playing only Galaxian this could be taken two ways -
Hey, I like PacMan too - how can I play it with this setup,
or
What program could be used to play horizontal games on a slower computer. (Had I seen that you liked Peale's Vantage suggestion, I might have assumed you were heading more this way).
I suppose I could have thought out my answer, but I thought by pointing out the obvious, if you were looking to add Pac-Man, you would have your answer. If you were asking about horizontal games, you would post back with "my bad - this is what I meant" (which you sortof did.)
Basically, I would just get a 200-600 Mhz processor (or better) and run an older version of MAME. Otherwise, look at what game you want to add, look at
http://caesar.logiqx.com/ and see what emulators it lists, and look at maybe Raine, Rage, Nebula, Final Burn, etc. depending on the game.