The best place to start, in my opinion, would be to download Unity and
start playing around. Maybe make a simple game like Pong (or whatever)
in 2D just to learn. Then move on to something simple in 3D, then VR.
I'd recommend coding with C# in Unity,...
It could be a security or anti-virus program that is blocking the
installation. There were known issues with both Comodo and ZoneAlarm
where you would actually have to uninstall them to get the Oculus
software to install correctly. Maybe can you look...
By default, no. Rift only natively supports games and apps that were
created specifically for VR. The headset remains off until a VR
application is opened, so you won't see you desktop or desktop apps
inside the device.