Nikon DX40x not taking pictures

there may be problem with the shutter inside the cam, should open and repair it.;

If one card works and the other doesn't then it sounds like you have a defective SD card. Nothing you can do about this but buy another one and toss it.

This is why you should backup all your photos off the camera and onto permanent storage media.

If you were hoping for a reason to replace/upgrade the camera I think this would qualify. If you want to see if you can save it, find a camera repair shop in your area and at least have it looked at. It may cost you a diagnostic fee but that will give you a better idea of whether it's worth spending the money on.

Same thing happened to mine. After researching the cost of a replacement screen, $60.00, I decided to replace the camera with an L20.
Otherwise here is a site for a screen, http://www.darntoothysam.com/categories/Nikon-Digital-Camera-Parts-and-Repair-Service/Coolpix-L-Series/

Try resetting the date and time.

I HAD THE SAME PROBLEM - HAD TO SEND MY CAMERA IN FOR REPAIRS. NIKON FIXED THE PROBLEM AT NO COST AS A CURTESY REPAIR.

There is something wrong with the settings of the camera.
When it is on setting or view mode is fine. It is not supposed to take pictures.
Go thru the Menu and pick the way you want your pictures, size and all those details, switch them take pictures and keep switching the settings until you get it right.

My camera was taking 3 pictures at the time, and it was because of the setting was set to do that. Don't be afraid of changing the setting for pictures, you can always change and try different things, digital pictures can be erased right away. So you can try as much as you want.
Try all options in the setting for taking a picture, change a setting, try to take a picture and see what happens. Then try on another setting and so on.
Artgirl

There was a recall on the N55 due to auto focus problems. You can do a google search or nikon.com email the support team and they will send you the paper. This is what I did, I wasn't charged since I had the correct papers. I, however, used one roll of film and my focus went out again! Mine doesn't even work on manual... If you want to try that maybe you will hae better luck than me. GOOD LUCK!

Try reseting the Cam !

You've just turned on the "highlights" option in image review. Press the up arrow on the d-pad to get back to the normal setting.