What is wrong with my DSLR Camera?

I own a Nikon d3200 DSLR Camera and when ever i shoot a picture a black mark appears in the top left corner of the file. It is not the Lens because when i swapped it it continued to happen.

Its difficult to diagnose camera trouble without seeing an example shot.

Sounds like it might be a speck of dust or debris on the camera sensor, best thing is to pop into a local camera store and ask if they can have a look, sometimes the debris can be removed by a quick blast of air. Its not something id tackle myself but others on here might encourage you to try and remove it yourself.

I've been lucky enough not to have experienced the same thing in any of my cameras. C All of your answers are in the manual. The sensor might be bad.
If it is, it could be expensive to replace.

In any case, solving the problem is not a D-I-Y job.
Consult a camera repair service. Are you seeing this in the computer? If you used a USB cable to connect the camera directly to the computer, try using a USB card reader to connect the camera's memory card to the computer's USB slot instead. If you are already using a USB card reader, try another one. If the problem persists, try a new bought and freshly formatted memory card. If still that black mark appears despite everything, bring the camera back to the store you bought it from and listen to what they recommend.

All of your answers are in the manual.

The sensor might be bad.
If it is, it could be expensive to replace.

In any case, solving the problem is not a D-I-Y job.
Consult a camera repair service.

Are you seeing this in the computer? If you used a USB cable to connect the camera directly to the computer, try using a USB card reader to connect the camera's memory card to the computer's USB slot instead. If you are already using a USB card reader, try another one. If the problem persists, try a new bought and freshly formatted memory card. If still that black mark appears despite everything, bring the camera back to the store you bought it from and listen to what they recommend.