the camera takes the picture as usual, but nothing shows up on the screeb except the images tags. like dsc:75739 or whatever it says.
when i connect the camera into the computer and read the card, the pictures are still black. my conclusion is that the sensor has failed from what i have made out.
soif anyone knows anything about how this works with nikon let me know, i called and they said to send it in, but i dont want to pay to have this fixed if its going to cost as much as just getting a new camera
Ship it to them, and they will likely give you and estimate as to how much it will cost to repair. Then ask you if you want to have it repaired or not. It's unlikely that they'll repair it if it would cost more than getting a new camera, and if that's the case they might offer to replace it at a slightly lesser cost than it would be to buy a new one.
And yes, something obviously went boom and died in your camera. No telling what it was; it might be as simple as a lose connection or as bad as some part of its internal electronics getting fried. Who knows. I wouldn't waste any time though in getting it sent to Nikon for and estimate/repair.
I would imagine the sensor would give some kind of error. It could also be your shutter has failed and isn't opening. Either way, not good. Check the latter by putting the camera into manual focus, removing the lens and taking a picture while looking in. Longer exposures would help you see this better.
Try one more thing. Take a longer exposure, say about 3-4 seconds. It could also be that your lens aperture closing down all the way and the exposure is just too short to show it on the screen. This could be a dead camera, dead lens, or just a dodgy contact. Again look into the lens to see if this is the problem.
Basically a Dark frame could be caused by a few things, and Nikon techs are idiots, so the more you could narrow down the problem for them the better.