I found this situation in PD14, likely it applies to earlier versions going back to PD9. As
Nick referred to them correctly, you can't remove those "prime" tracks, being Video Track 1(master) and Video Track 2(Picture-in-Picture), but other video and audio tracks can be deleted if not required. It's been my observation that each time an item is dropped onto Video Track 2, Video Track 3 is automatically added, and should you add something there, Track 4 is automatically added, and another track will be added each time. There's no automatic deletion of the tracks when added, but each unused(empty) track can be individually manually deleted. This applies to the extra audio tracks which are added along with the video tracks. I have noticed that if an extra track is added manually(
a video track added without audio) PD will, if that track is filled, add another video & audio track. Whether it does this when just the audio track is added, I've not tried that so can't say for certain. As for "Remove Track" being greyed out and "Remove Empty Tracks" doing nothing, could be a trial version or a corrupted programme. They're my guesses, though they could be well wide of the mark.
Cheers!
Neil.