Part of a computer that's been knocked off? (4)
I believe the answer is:
chip
'part of a computer' is the definition.
('chip' is part of 'computer')
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for chip that I've seen before include "Token - golf shot - potato piece" , "Approach shot at 1 across" , "Small fragment (of potato?)" , "Gambling counter; golf shot" , "Small fragment of wood" .)