Confess to being mad about computer stuff (5)
I believe the answer is:
admit
'confess to' is the definition.
(I've seen this before)
'mad about computer stuff' is the wordplay.
'about' is an anagram indicator.
'computer stuff' becomes 'it' (I've seen this in other clues).
'mad' is an anagram of 'adm'.
'adm'+'it'='ADMIT'
'being' acts as a link.
(Other definitions for admit that I've seen before include "Confess - acknowledge" , "Reveal" , "Allow access" , "Provide student with place" , "Confess and permit entrance" .)