Nikon D5100 wont flash - Nikon D5100 Digital Camera

Here is a list of things to check:
1. Go into the camera's menus and make sure that the flash is enabled.
2. Check in the menus that the flash is not set in the command mode.
3. You didn't say if your camera was in the auto mode, aperture or shutter priority, etc. If the camera is in shutter priority or manual mode, make sure that the shutter speed is below 1/250th of a second.
4. Make sure that the ISO speed isn't set so high that the camera thinks that flash is not needed.