I have tried all suggestions but I cannot get my applie TV to "find" my network.

Apple Tv is now finding the network, then it's not, then it is, then it's not. Constantly saying "there's a problem with the network or connection error".

We managed to sort it once but as soon as we changed application ie went onto Netflix or iTunes it disconnected from the Wi-Network. It then takes several attempts and several restarts to get connected again. Any ideas.