Panasonic Viera TV guide?

Hi, my in-laws have a 26" Panasonic Viera and they seem to think there is something wrong with the handset, every time they turn the television off regardless of which channel they are on it always turns back on channel 17. Having had a 'play' with the controls it looks like the actual TV guide accessed through the handset seems to have disappeared. The only way they seem to be able to change channels is using the numbers on the handset, using direction arrows sends them to all sorts of channels. Any advice would be very much appreciated.