Channel Guide: When I'm surfing channels using the Channel Guide - it will jump 20 - 50 channels, frequently

1.  Channel Guide:   When I'm surfing channels using the Channel Guide, it will jump 20 - 50 channels - frequently.

2.  When watching a recorded program, (like the news) the picture stops or flutters or distorts, etc. The sound does about the same.  Not reliable!