B.R.
i had the same problem with my son he is now 12 but this is how i handled the problem....
after a few weeks of him i want this no i want that,
the first thing he ask for is what he got i told him
you asked for barney not the big bird now you can watch barney and after that you can watch big bird, if you don't want to watch it go to your room and play, but idf you throw a fit and scream and holler you will get time out(my time out is one min. for every year so it was 4 mins.)it's not long but to them it's a eternaty, he will or she will try you on this but stick to your guns and it wil work it took 2 weeks with my son.