I write this message because I want to thanks all people of this forum because with their discussion helped me to build a computer in order to play my beautiful Galaxy 5.1 piano in live gig.
I bought a little barebone Asus Pundit-R with P4 2,8Ghz 800HzFSB 1 Gig RAM.
This computer has a slot PCMCIA where I inserted my Echo Indigo sound card and a lot USB2 port where I inserted my Midi interface.
Pundit has TV out where I can connect a little 7' monitor to launch galaxy and I mounted this little computere in a little bag.
With this configuration I can play live gigs with a great sound of piano (I play jazz) with 4ms latency so this solution is simple like a hardware expander.

Thanks to all especially to michael88s who started an interesting topic in this forum about live piano system.