You may have an issue with heat and your STB. Is it in an open location - well ventillated?
Are you using HDMI? See the following FAQ and things to check:
http://www.digitalhome.ca/forum/showthread.php?t=71112
Are you using HDMI? See the following FAQ and things to check:
http://www.digitalhome.ca/forum/showthread.php?t=71112