Lots of questions..
Tip: Read (all) old messages, and I think you can find an answer to 95% of your questions... They all have been covered before..
Nope... the parallel-port of your pc does not supply 5v. You have to get this somewhere else.. (like gameport, keyboard, or just directly from the computers' psu)The way I see it, the display will use the printer port for power, but the backlight needs current from elsewhere with the two pots controlling contrast and brightness.