Funny thing about remotes..... is?
at least in my experience, Human Error....!
most remotes have a line of buttons (usually 4 in a row)
such as: TV, VCR, DVD, AUX, STB, TV/RAD, TV/SAT, ect.., etc...
STB is the one you want to use.....
my fat fingers are notorious at accidentally hitting a wrong button and causing the receiver to not work. panic, fear, and an untimely amount of stress occurs before I realize my misfortune
but, it's always a relief to find out it's something simple
hope your problem is as simple as I suggest
Good Luck..!!