blocked might mean your hdtv tuner doesnt have the 'permisson code' to unblock the channels.
if you are paying for the channels, you might be able to get the tv tuner programmed by the television company.
although, this seems a bit childish when the tv tuner is supposed to see that kind of programming when connected to the cable.
i havent had to upgrade anything, so i dont know if the cable companies prefer to make you bring in the box to be programmed so there is no way for you to learn the permission codes.
maybe they dont program the box over the coax cable.
it isnt really a problem when they have security in their best interest.
you know, maybe they send a technician out with a special computer that programs the tv tuner so you...