Does anyone have a NOOK?

It depends if it was the nook 1 or the new one. the nook 1 was known for being slow. idk about the new one but it was supposed to be a lot faster. The nook 1 does freeze and it gets kind of annoying. if you mean that the screen flashes to black it is normal and it can't be helped. it's in all eReaders. its just the eInk getting rearranged.