My hp windows 7 home premium notebook pc is diplaying sideways?

Hello,

Turn head sideways to match your screen (so it looks proper), right click on your desktop, select screen resolution, now click on the option that says "Orientation" - Make sure it's on "Landscape" any other one will make your screen go wacky :)
 

HugoStiglitz

Distinguished
if its an intel graphics chip there is often an icon in the bottom right next to the clock (when not rotated) that allows you to rotate and change resolutions

there is also a shortcut keyboard command that can activate the sideways screen which is how it happens in the first place normally.