could be 2 possible senarios. the first being your tv number 1 needs to do a channel scan so it can find the channels and program them into your tuner, the channels might be there just not picked up by your tuner unless you add them.
Or, the channels were removed as part of the Analog to Digital migration and you were tuning into them via analog, and now need a Digital Transport Adaptor (DTA50) to tune them in now. which is free of charge provided by rogers video cable stores.
Jmullan, are you using any digital box? or is this just straght from the wall into the TV?
Starting over 2 years ago, the analog to digital migration started. It started with all of the over the air signals between stations, etc being in only digital. This means, for rogers to distribute analog, they actually need to take an extra step/hardware to convert it DOWN to analog.
They have been annoucing the removal of these channels since back in that time.. more analog channels removed every month.