most remotes don't access the tv's input selector.. Use the TV remote.
Or the HDMI cable is unplugged, cable box is turned off, etc...
The new remotes with the master power sequencers are garbage, they end up with the cable box and tv out of sync. Try turning on the cable box seperately, then don't use the master or system power button...
This is worst with the cable box that's missing the clock... seen the issue first hand... It may be the CEC interactivity as well as the CEC will try to turn off the tv when the cable box is shut off. You may need to turn CEC off in the TV if it has the option, else you need to put a pin 13 CEC stripper inline.
There is no power saving by turning off the cable box... just turn off the TV.
For your first concern, this link will take you to the different remotes that are offered and how to program them!
Beyond that, however, the "no signal" message is from the Television itself.
A few things to check: are the lights on the front of your cable box? If so, is the power-indicator on? Press the power button on the box a few times and see which light goes off or on whenever you do - and then make sure it is on.
Once you've done that, if you still have "no signal" then make sure the wire that connects your cable box to your TV is in place on both ends.
If it is in place, then you will need to change the input setting on the TV. While it would best to use the remote that came with the TV, you can also use the buttons on the TV itself, and (in some cases) once the remote is programmed, there is a button on many models that says "video source" in the bottom left corner.
On the TV or TV remote there should be a button labeled "input" or "source" or "video source". If you press that it should bring up a list of available inputs on the TV. Try each of them until you find the one that has a picture.
If those steps do not work, please let us know and we'll see what else can be done for it.