Pc Wizard
someone who does something normal with computer but technologically impaired person (usually family member) see it and gets amazed by it and then suddenly that someone knows EVERYTHING about computers.

also them related words are: mac sucks donkey balls
how do be a Pc Wizard:

Tim presses alt + tab to changed windows.
father sees it and says:"Oh Tim how did you do that?"
later father tells his friends that Tim can fix anyones computer.