Win perhaps playing in Ulster (6)
I believe the answer is:
result
'win perhaps' is the definition.
(I know that Microsoft Windows is a operating system)
'playing in ulster' is the wordplay.
'playing in' indicates anagramming the letters (I've seen this in other clues).
'ulster' is an anagram of 'RESULT'.
(Other definitions for result that I've seen before include "Outcome of an undertaking" , "Verdict" , "End - issue" , "Ulster (anag) - outcome" , "'Outcome, upshot (6)'" .)