My Nikon d3100 won't take a picture with flash, why?

I have this Nikon D3100 for less than a year now, but suddenly I whenever I try to take pictures with the flash, it doesn't work. The camera will take pictures on the no flash settings, but when i put it on auto, or any other settings it won't work. The internal flash will pop up and It will focus and make the beep sound like its ready to take a picture then, no picture will be taken. If I hold the internal flash down while i take a picture so it can't pop up, then the camera will finally take a pic. I really hope this isn't an internal problem, because i don't have a lot of money to get this repaired.

If you've had it less than a year, take it back where you got it and explain the problem.

Unless you've dropped it, it could be fixed under warranty.