All pictures taken are just Blackness

Did you try to press the info button several times? Whatch what happens on the screen, because the camera will cycle through several views.
It is in the manual, under Changing the image information display.

See Chapter 5, "Live View Shooting" in this manual.

make the "live view"/"viewing screen" first enable by locating it in your menu or your settings. then after that you can go back from taking picture by using the viewing screen

in regards of viewing the pictures taken, press the display button. keep pressing until the viewing screen appears

this means that the plug from the lcd is out ..and i need s to be open and put it back ..probably a shock ( mechanical) it is to blame ...cause if you remove batteries it should be reset itself to defaults and have preview picture...also ..with that buton on the back moved to the right should bring the picture view on ..to see the last pic taken or the picture in teh memory ..if the display os black most af the time it means that it has an imperfect contact but is still functional and only the ribon that it is plugged on it and makes communication with the unit its to blame ...if you are handy you may try to open it ..but I advice just to get help cause its tricky ...and sensitive ...

You have to set the camera to "Live View" mode. Check your manual for settings.
BTW, it's usually a bad idea to use Live View mode unless the camera is on a tripod. With Live View you have to hold the camera out in front of you and it's much less steady.

Really? Your lcd screen might be damaged! take it to someone who can tell if a pixel is damaged or not.

You can choose whether or not to display the picture you have just taken on
the monitor.
ON : The picture being recorded to the card is displayed. This is useful for
making a brief check of the picture you have just taken. You can
resume shooting anytime during REC VIEW.
OFF : The picture being recorded to the card is not displayed. This is
useful when you want to prepare for your next shot while the
previous picture is being recorded.
1 In the shooting mode top menu,
select MODE MENU
SETUP

REC VIEW
OFF or ON, and press

Sadly the D40X does not have a live view function. You can only view shots you have already taken or use the display to make adjustments to the settings.

Currently the only Olympus digital SLRs have live view.

Does the screen deliver anything such as menu. Or can you see ghost images if looked at from the side? If you see nothing then this is a connector issue of a circuit board failure. If you see ghost images then it a back light failure. Either way this is a return to HP situation. If under warranty via the seller if not under warranty contact HP customer support. If they are quoting money- you may find it more economic to write it off and get a new camera.

Nikon Techical Support the quickly this is a CCD or associated component failure