Nikon d50 not taking pictures?

I have a d50 it takes pictures but the sutter stays closed i have to press again for shutter to open again and when i check memory no pic is take i also don't see the memory light go off indicating its saving tried resetting menu and camera not working any ideas?

Added (1). I got the camera to work there was junk in it blocking i gues the sensor when the mirror went up in any one needs help what you do is put the wheel on M and set the settings to bulb then shut off the camera and take off the lens while still on bulb press the shutter and the mirror will go up if everything is fine then the mirror should drop of it doesn't drop open the little black door at the end and clean your camera cause some thing is blocking it and thats what stops u from getting an exposure i guess i did this and fixed it by luck i'm no pro but it worked for me my camera works great now good luck

Added (2). I got the camera to work there was junk in it blocking i gues the sensor when the mirror went up in any one needs help what you do is put the wheel on M and set the settings to bulb then shut off the camera and take off the lens while still on bulb press the shutter and the mirror will go up if everything is fine then the mirror should drop of it doesn't drop open the little black door at the end and clean your camera cause some thing is blocking it and thats what stops u from getting an exposure i guess i did this and fixed it by luck i'm no pro but it worked for me my camera works great now good luck

Sounds like you enabled mirror lock-up. In that mode the first time you press the shutter, the mirror will go down, only the second time you press the shutter the photo will be taken.

As for why there are no pictures after you press it the second time, you might want to get it checked at a camera store.