scene and game screen is invisable (default layout is active)

I’ve uninstalled and reinstalled about 5 times now, I can see nothing but a dark grey screen in the scene view or blue in game view, I select the camera in the Hierarchy, it doesn’t make a difference, I’ve looked at the scene space in all different angles using the perspective gizmo, I just don;t understand what I’ve done wrong as it was there originally. It seemed to disappear when I was using the scrolling wheel on the mouse to move closer to the camera icon in the screen view. Is there just some simple key press to turn it all back on? I also tried opening the platform 3D tutorial found on unity’s website, it opened fine but when I dragged an assset into the scene view nothing showed.

Please help someone so I can start using Unity, I was told it was it was a better put together engine than UDK, but this is just becoming frustrating now

Thanks

A couple things to try:

In the top right corner there should be a box that says layers, make sure the default layer has a check by it.

Double click on an item in the scene hierarchy and the editor camera should center on that object.

You can also select a game object in the hierarchy and go to GameObject > Align view with Selected