How can I tell which OS my MPC 4000 is running on.

I just picked up a used MPC 4000 and I was wondering how I might figure out what operating system it is running.

Why not try switching it on and watching the screen?
It will say which version it is running as it boots up.






Alternatively.....
If the MPC is already on, Press the GLOBAL button, and then press f3 [config].

Ty