Hi Kelly and
,
Have you tried rebooting the DTV box?
Just unplug it at the wall and count to 15.
While it's unplugged, take the card out and make sure that the contacts etc on the card are free of dust and other fluffiness. Make sure you wipe it gently (a soft, lint-free cloth is best).
Now put the card back in (making sure that it is seated correctly in the slot) and power the beast back up.
Leave it a while and see what happens.
You will find that it
looks like it is ready after a minute or so, best to leave it 5 minutes or maybe a bit more before you try changing channels.
If that doesn't work then I'm afraid I don't know what to suggest.
What area are you in? Maybe somebody else is having similar problems.
Good Luck!