When I turn on the camera, the screen is black

This appears to be a deeper problem than can be fixed with advice on here. I suggest you take it for a professional repair. Check the repair estimate with the value of the camera.

Your camera needs to have a function called "live view".

A number of things could be wrong.
See if you can get the menus to work correctly.
If you can see the menus then the problem is not in the playback system, but in the taking part of the camera.
Could be a ccd problem if the menus are okay.
If you can get the menus, set all to default, and then test it.
If the menus also shows the bad picture details as you have described, then the camera needs repair.

Try cycling through the Display button until you're able to view photo to be taken.

Turn the camera on. With the screen showing, press the DISP button and this will give you a selection of different screen views i.e. squares for aligning shot squarely; black - thru viewfinder only; etc. Different modes will give you different screen displays i.e. P setting screens are different to when you have the camera set on AUTO.

Hope this helps.

If you were seeing the image before you shoot, there was definitely something wrong with your camera.

The D40 does not have a Live View feature. The display is for menus, shooting information, and image review. Not preview.

it is LCD problem , it need to open and clean the black pattern...

Hope this may help;

Perhaps you have quick view turned off in the setup menus. There's no way the CCD is the problem as the camera takes pictures.

No solution for your first problem but it's normal that you cannot view your photo on the LCD screen before actually taking it. Due to the way a reflex camera is built, you can't have a live view on your LCD. The Fuji S3 Pro has this type of preview as also most recent camera (Nikon D300, Canon 40D...).

CCD failure most likely. Format the card then try again or a new card. Kodak customer support for more info