Hi there,
Tykeman is correct - I didn't see this post y'day else that's the first thing I'd have suggested. I re-set my 2 Sky recievers aout once every 2-3 weeks, if I forgoet, it's quickly bought to my attention when a short while after one of the household will report 'ohh look that channel isn't working' - quick unplug, leave for 30s seconds to a minute, plug and power back on and all is good!
Cheers! DtM! West London & Slough UK!