I think they mean the lock slider on the side. This will bring it up into another menu.
I have seen a CF mod H120 where the CF adapter slid out of the place where it plugs in... the CF card and adapter are smaller than the original hard drive, so there is room for it to become disconnected. I ended up putting a piece of something in there to keep it so it doesn't slide out again.
At any rate, if you want the shows that are on there, probably the best thing is to take it apart, remove the CF card and copy the data off there via card reader before you mess with the H120 too much.
PS: If you are at your wit's end, mail it to me (Maine) and I will take a look.