My camera won't work. The view finder is out but won't go back in therefore I can't turn the camera on or off.

The view finder is the little window on the top left of the camera. If you want to use the display as a view finder, you have to press the button with the camera logo. It is called the life view mode. you use the same button to switch off the display. Be aware using the display, will drain the batteries quicker. Somewhat faster then with modern cameras.
see page 19 of the manual.

Push your shutter 1/2 way down. See whats the readings in view finder.

About the only thing I would suggest is check the cables to make sure they are in properly but that won't change much as far as it operating intermittently. I think the best thing I can suggest is just take it back and have Santa's Elves exchange it for a new one.

You probably turned the dioptri-adjust button, next to viewfinder, by mistake. Turn it back until the viewfinder is sharp.

If you can view previously recorded tapes and see icons on the LCD, you may have an image sensor (CCD) problem. See this link regarding a Canon service notice about this issue. If you think this is your problem, contact your regional Canon service facility.

Im afraid your camera does not have live view so therefore you will have to use the viewfinder to take your images and view them back on the lcd screen.

The Nikon D40 camera does not have "live view".

Thanks.

Is the battery dead? Try taking it out and charging it, then put it back into the camera.

Also, you can try using another battery of the same type.

With the camera on, have you tried pressing the DISP button once? It's the lower left button on the back of the camera. It manually turns the display on or off as desired to save batteries (you can then aim through the optical viewfinder).