This might be because you set your Viewpoint Render Distance VERY low.
Select an Object you want to center your Viewpoint on Press "," on your Numpad to center your view.
Next in your "N" menu on the right side of your "3D View" set in the tab "View" your Clip: Start: 0.1 and End: 1000
This should resolve your Problem
Edit: To check if your Object are outside of your visible Area. Select an object of your by using the outliner window, by default top right.
Now you either can center your view on this object using the method above or press "space" in your "3D View" and type in "view selected" if this still does not work Check if your are in the right layer of Blender.
You can check this with the "20 Layer Buttons" in your "3D View's Toolbar"
An orange dot means this is the layer the item is in.
A grey one means there is an object but its not selected.
By pressing on the buttons you change your layer view press Shit + the ones you want to select multiple layers.