Why are my pics fuzzy when i turn flash off on Nikon D40?

I'm using a Nikon D40, when the autoflash is on, the pics are crystal clear, when i turn the flash off for a more natural shot the picture is always fuzzy regardless of how still i hold the camera. Any ideas, I'm really a novice here so I literally have no idea about DSLR's and what they can do, this camera was kind of inherited.

This could be because the ISO settings have been altered to a higher setting. Higher ISO settings cause graininess in the images. Most DSLR cameras have a ISO range from 100-64000. Change the setting to 100 (the option should be clearly visible in the options menu).

Also, when shooting in low light conditions (no flash) then the effect of having a much higher ISO is more obvious and therefore the grains. Having the the flash on simply stops the grains from appearing.

Hope I helped.

They are not "fuzzy". What has happened is you are attempting to take a photograph in low light and the shutter speed is so slow, the camera movement during the exposure.

You need to make sure that you do not hand hold the camera when the exposure is longer than 1/250th second until you get very good at holding the camera real steady. Unless you have the camera on a tripod, there will always be just enough cameras movement to create slightly blurred shots

Here is how you balance the ISO, shutter speed and lens aperture

http://camerasim.com/camera-simulator/

It is fuzzy because the camera is detecting there's not enough light and therefore to compensate for this a slower shutter speed comes into play. No matter how still you think you're holding the camera there's going to me minute movement.

Under low lighting conditions, the camera will be forced to take the shot for a longer period of time to get the right amount of light. The longer the shot is taken, the more prominent blur will appear. That's where the fuzz comes from.

You need to understand the basics of exposure. Where there's not enough light, the flash is used to supplement. If you do not use the flash you have one of three options, all of them will affect the sharpness.

1) Open up the aperture up (use a smaller f/number). Most lenses lose sharpness at wider apertures, plus less of a scene is in focus so you need be more accurate with focus

2) Slow down the shutter speed. There's a limit to how still you can hold a camera, this is usually defined by the 1/focal length rule. So if you're shutter speed dips below that value you need to use support (either with a monopod, or for very long exposures, a tripod).

3) Increase the ISO. Increasing ISO will allow you to use a shutter speed that you can handhold with. The cost is interference which is called noise, and this will cause a certain degree of softness, and loss of detail.

If you don't understand what I said, then I would strongly advise you read a book on photography.