If you placed your default view to a sheet, you want to rename it and create a new 3D view by going View > 3D View > Default 3D View. This way the view on the sheet won't be affected, by using your default view.
I assume that with a "box" you mean the Crop Region. You can deactivate the feature by clicking the Crop Region button on the View Control Bar, at the bottom of the window.
The "skewness" of the view seems to be caused by having the perspective on. Set the Projection Mode to "Ortographic" from the Properties panel.
Hope this helps.