Slow shutter My camera, suddenly, developed a slow shutter. Is there a setting that might have inadvertently been changed to cause this?

What mode are you shooting in? It seems you may either have your shutter speed set manually to a slow speed or, alternatively you have set your apperture set to a high number e.g f/20 or there abouts. Because this is a very narrow apperture the camera will compensate by using a slow shutter speed.
Try some shots in fully automatic mode and see what happens. With a slow shutter speed you can expect any movement to produce blurred images.

The pictures are blurry due to camera shake, which in itself is caused by the slow shutter speed. Try using shake reduction setting. To increase the shutter speed, raise the ISO rating.

Blurred images are caused by several reasons: motion due to camera shake, use of slow shutter speeds and failure of the camera to focus correctly.

Slow shutter speeds

When light is low, wide apertures and slow shutter speeds will be selected automatically by the camera. Most people can't take blur-free, hand-held shots when the shutter speed is under 1/60th of a second.

Cameras that have optical Image Stabilization help but even IS has its limits. Increase room lighting, increase the ISO setting or use a tripod, or use a combination of all three.

Blurred images or misfocus

If an image is blurred due to camera shake, the blur will appear throughout the entire image. If parts of an image are in focus, and others are not, you've misfocused.

This is a common problem if you are taking pictures in low light with out using the flash.
I suggest to set all settings in your menus to factory settings. Then set them the way you want. This may change some settings.
Always either have the camera on a solid surface or use a tripod when you take slow shutter pictures without the flash.

http://www.digicamhelp.com/taking-photos/advanced-techniques/shutter-speed-chart.php
click the link.

Two possibilities : 1 ) your film was not properly loaded into the pick up spool and hence it was transported or exposed ; what you took to the lab was unexposed film. 2) the shutter is not opening and again no exposure takes place. To check this open back , set to slow speed like 8th of a second, and see if the shutter opens and closes properly. If the shutter does not open then it will have to go in, unfortunately. Cost ? If it is just an adjustment ( as I suspect is the case ) you should not pay more than $ 100.

It is possible you have the Flash Mode set to one of the Slow Sync modes (lighting bolt with the word Slow). Slow synchronization flash sets a slow shutter speed for the background exposure and fires the flash for the subject exposure. Since the shutter speed is slow, your subject should be still and the camera should be on a tripod otherwise blur can result. Since this mode should only be used when the above conditions can be met, you should use the FILL-IN FLASH (single lighting bolt symbol) mode for most situations that require a flash for correct exposure. Repeatedly pressing the FLASH MODE button will cycle through the various flash mode settings.

It is possible you have the Flash Mode set to one of the Slow Sync modes (lighting bolt with the word Slow). Slow synchronization flash sets a slow shutter speed for the background exposure and fires the flash for the subject exposure. Since the shutter speed is slow, your subject should be still and the camera should be on a tripod otherwise blur can result. Since this mode should only be used when the above conditions can be met, you should use the FILL-IN FLASH (single lighting bolt symbol) mode for most situations that require a flash for correct exposure. Repeatedly pressing the FLASH MODE button will cycle through the various flash mode settings.

It is possible you have the Flash Mode set to one of the Slow Sync modes (lighting bolt with the word Slow). Slow synchronization flash sets a slow shutter speed for the background exposure and fires the flash for the subject exposure. Since the shutter speed is slow, your subject should be still and the camera should be on a tripod otherwise blur can result. Since this mode should only be used when the above conditions can be met, you should use the FILL-IN FLASH (single lighting bolt symbol) mode for most situations that require a flash for correct exposure. Repeatedly pressing the FLASH MODE button will cycle through the various flash mode settings.

It is possible you have the Flash Mode set to one of the Slow Sync modes (lighting bolt with the word Slow). Slow synchronization flash sets a slow shutter speed for the background exposure and fires the flash for the subject exposure. Since the shutter speed is slow, your subject should be still and the camera should be on a tripod otherwise blur can result. Since this mode should only be used when the above conditions can be met, you should use the FILL-IN FLASH (single lighting bolt symbol) mode for most situations that require a flash for correct exposure. Repeatedly pressing the FLASH MODE button will cycle through the various flash mode settings.