Elle ne regarde pas la télé.

Question

Wouldn't this be: elle ne regarde pas de télé ...using "de" after pas?

Answer

using 'de' after the negation is when you negate the thing after the verb. In this case, the negation is about not watching so it is a simple negation of the verb 'regarder'. 
'Je n'ai pas de frère' is about no brothers. The 'de' in this case is like 'any' in English. 'J'ai des frères.' I have brothers. 'Je n'ai pas de frères.' I don't have any brothers.

Answer

Hi Helen, 
We always say:
Elle ne regarde pas la télé = She doesn't watch tv
Ils n'écoutent pas la radio = They don't listen to radio
Nous ne parlons pas le français = We don't speak French
Ses enfants n'aiment pas le chocolat = Her children don't like chocolate
It has nothing to do with the pas here.
If you say:
"Il n'a pas de télé" ( téléviseur), it means, 
"He has not got a tv"
Hope this helps!

Answer

Why would it be Il n’a pas DE télé and not ....pas le télé?  Why use “de” not “le”?

Answer

The rule in French is when you are using negation to say there isn’t any of something, the definite article goes away and is replaced by ‘de’.   « Il n’a pas de télé. » means he doesn’t have a TV set. Il a une télé. means he has a TV. Similar to what happens in English when we say “He has some ideas.” When that is negated “He does not have any idea.” The word ‘some’ changes to ‘any’. It’s one of those idiosyncrasies of language. Hard to explain but when you start using it correctly, your French will sound so much better.