Pretty short question, so I'll sum it up in a couple words (If you don't know what I am talking about, it's the bar on the top of the screen that has three buttons up there signaling chat, menu, etc.) Is it possible to disable the bar, and if so how?
TheDeadlyPanther is right, however you can set its transparency.
local playergui = game.Players.LocalPlayer:WaitForChild("PlayerGui"):SetTopbarTransparency(1) --number 0 to 1.
This must be a local script, and has to be in StarterGui or StarterPack to work!