power user 
noun Computing
A knowledgeable and sophisticated user of computers.I would imagine that most systems not set up by a professional admin or a power user are running from the admin account by default, because most users are unaware of the security benefits of isolating, or sandboxing, users....
- Even within broad categories, be it a power user or a novice, per user approach differs.
- Whereas previously it was limited to specialists and business analysts, it has extended its focus to include power users and business users.
- two-dimensional
- two-dimensionality
- two-dimensionally
- two-door
- two-edged
- two-faced
- two-facedness
- twofer
- two fingers
- two-fisted
- twofold
- two-four
- two-handed
- two-handedly
- two-hander
- two heads are better than one
- two-horse
- two natures
- twoness
- twonk
- twoonie
- two (or three, four, etc.) of a kind
- two (or three) sheets to the wind
- twopence
- twopenn'orth