Troubles of computing stopping American businessman (8)
I believe the answer is:
agitates
'troubles' is the definition.
(agitating is a kind of troubling)
'computing stopping american businessman' is the wordplay.
'computing' becomes 'it' (IT is an abbreviation for Information Technology).
'stopping' indicates putting letters inside (stopping can mean blocking a gap).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'businessman' becomes 'gates' (Bill Gates).
'a'+'gates'='agates'
'it' inserted into 'agates' is 'AGITATES'.
'of' is the link.
(Other definitions for agitates that I've seen before include "Disturbs or stirs up political trouble" , "Tries to stir up public opinion" , "Disturbs, often politically" , "Upsets" .)