Guide problem - 1 channel

[suible]

I've been using the Guide for months - same cable provider, zip code, channels, etc, using same settings (maybe 45-50 channels). Suddenly it is down to 1 channel - when I went to change channel lineup, it gave me a choice of exactly 1 channel (for cable). I'm using Cox Cable in Phoenix area - and the one channel that the guide does show is actually a channel that doesn't comes through without the cable box (which I don't have).