There is insufficient information to know what is wrong with it or if it can be fixed without sending it to a service center. If there is a defective component then, you will have to go that route but there are several things to try before:

• First, since you said the settings show, perform a camera reset. There is a Settings menu where you will find the Reset option to reset the camera configuration of menu items to their default.
• Second, the exposure may simply be off which will not be fixed by the reset since dials are involved. To check this, move the Mode Dial to the Auto or P position.

Try to take a photo after doing the above. Listen to the camera carefully. You should hear 4 sounds: a loud one when the mirror goes up, two quiet ones when the shutter opens and closes, followed by a loud one when the mirror goes down. While the mirror goes up and down, the viewfinder will temporarily black out. If that does not happen, then you need to have it serviced to fix the mirror mechanism. If you hear the loud sound but not a low one, then it's the shutter that is broken which also requires servicing.

Unfortunately, if you hear both sounds after having reset the camera then you probably have a more expensive problem to repair such as a dead sensor. Those are too expensive to practically fix for an old entry-level camera and it will cost significantly less to buy another working camera in the used market. The good news is that you can expect a much better used camera for the price of fixing a sensor.