Looks like we got a time delay here.
I`ll start with the original message that said " Sorry this channel is not available " , although you did not give me the tv`s full model number ,i`m pretty sure this message does not come from a sharp tv but whatever equipment you have connected to the tv like satellite box , cable box , freeview box etc. and that would have been the one that needed checking .
Now with this snow , i believe that you simply changed the input on this tv from where it was set to connect to the said (above) equipment to antenna/cable input of the tv where nothing is connected now hence the snow.
Look on the tv`s remote or the tv itself for a button called INPUT (or SOURCE)and press it repeatedly to get back to the input where it gives you that message.
Right now without any further details on how you are receiving your tv channels it would be difficult to say what the exact problem is but again this problem /message is not related to the tv itself , your tv is fine i`m sure and it is the associated equipment and its signal that needs to be checked .
If you have a cable company or tv service provider then contact them to verify their equipment but on the other hand if this is freeview for example then ask whoever installed it to check its wiring and perhaps reboot the box by pulling out its power cord for a couple of minutes.
If you do not have a provider and that message does come from the tv itself then please let me have its model number and connection type (antenna/dvb/satellite) ?
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