Faded out the answer to what started Norton on the radio (5)
I believe the answer is:
ended
'faded out' is the definition.
'started norton on the radio' is the wordplay.
'started' indicates taking the first letters.
'on' means one lot of letters goes inside another.
'the radio' becomes 'eded' (I can't justify this - if you can you should give a lot more credence to this answer).
The initial letter of 'norton' is 'n'.
'n' going inside 'eded' is 'ENDED'.
'the answer to what' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
(Other definitions for ended that I've seen before include "Concluded" , "Broke off; finished" , "Culminated" , "wound up" , "Over; complete" .)