Help a frog

[inetbox300c]

Hello there,

I am new and I understand only a little bit.
I was given an Inetbox (=DM500 I understand), I restored the factory defaults and browsed the cable channels (TNT France).
I can see the channels, see the channel infos but no image, no sound.
If I switch to radio channels, it works fine.
Any suggestion?
Also where can I find canal+ (F1 being broadcasted by them since 2013)?
Thanks a lot

[GastonJ]

You need to go back to the person who gave you the STB and ask them for the config file that you have deleted when you set it back to default.