Greatings

I came here with an very strange situation.

A few days ago, my one year old kid was playing with the remote command of a
little bed-room Sanitron TV, switching channels, AV, back to channel,
volume up, volume down, pressing every key... you know kids
Then a bizarre thing happened:
Somehow my kid punch a sequence or a combination that had put on screen a
technical menu that i've never seen before.
It had a red description on top, a vertical green list of itens with
abreviations and numbers and tree color bars (red, green, blue) on the
screen center for individual color ajustments... I don't know how many
minutes he was pressing keys on that menu, when i saw that i took off the
remote from his hands e try to shut down the menu widout any luck, so i
shut down the TV in it's main switch.

Turn it on again and it looks normal at first, but then i notice many
missing channels , i have cable tv with more than 50 channels and now i can
only see about 20... When i've tryed to memorize the channels again i
realize that the TV only receves from C01 to C20 and S01 to S41... all
frequencies from C21 to C69 only come out with no signal white
interference. So i realize that the UHF receiver is not working.
Somehow the kid desconfigured the UHF receiver, and my favorite channels are
on UHF.

I've been trying to get access to that menu with no luck.

Friends, i do have a few understandig about electronics but i am not a tv
technician (in a way, i am a electronics car technitian)... can you help
me?
Can you teach me how to go to that menu and try to reconfigure things in
there? Or is there a way to reset things and put everything back on factory
defaults?
Will i be going to put the tv in the trash for this stupid situation?

Many thanks
Amarok (from Portugal)