How do I tell which operating system I am currently running

Have just got a MPC 1000 second hand today, and was wondering if there is any menu or anything on there which shows which operating system you have currently installed, so that I can download the latest one if there is still an old one on there.

I think it is MODE + OTHER, then it will state your OS in the upper left corner.

1.07 is the latest btw.

Thanks man, I'll give it a try