Country's aim - installing good network (7)
I believe the answer is:
england
'country's' is the definition.
(country of the United Kingdom)
'aim installing good network' is the wordplay.
'aim' becomes 'end' (both can mean a goal or purpose).
'installing' means one lot of letters goes inside another (inserted letters are installed).
'good' becomes 'g' (abbreviation).
'network' becomes 'LAN' (Local Area Network).
'g'+'lan'='glan'
'end' enclosing 'glan' is 'ENGLAND'.
(Other definitions for england that I've seen before include "Dan Glen is a neighbour" , "... and its World Cup holders" , "Lend nag out to the country" , "Cricket team" , "CARRY ON FILM" .)