Dual screen/USB formatting on Linux

[Buhaj]

I was using Linux on my old laptop for a while, and two things were annoying me:

• when I was using dual screen mode (connected an external screen to my laptop), I couldn't turn off just a laptop screen so that I can watch a movie on another;
• I installed a Ubuntu instance from a USB drive, but then in Linux I couldn't format it so it works like a "normal" USB drive; had to use Windows.

Was it something I was doing wrong, or is Linux not offering those functions?