Greetings!

Go to the "about" option on the player menu. It will tell you the version of the main firmware (likely to be 2.0). As for the version of hijack, if it is loaded (and somewhat recent) there should be a boot popup with the version number. If not, set up a serial link and watch the boot log. It will show you there as well.

As to the space, 450MB of 55.7GB???!!!??? You might want to use emplode to search for files with zero references. The person you received it from may have deleted their playlists, but didn't actually remove the music from the player.