Why won't my Camera photos upload to the computer?

I have a Nikon Camera.
Before today It would upload the photos to the computer with a plug in about 5 seconds.
But for some reason I plugged it in today and it won't let me upload any, It says "USB Device not recognized". And I've re plugged it whole lot, it still won't work.

Any suggestions?

Hmm

Why don't you do what those of us who have been shooting with digital cameras for over a decade do?

Remove the memory card from your camera, insert it into the card reader on your computer and using your computer skills, copy all the images from the card to a new file folder on your computer named for the subject/location and date so you can later find them again.

Once they are safely on the computer, format the card using the format feature on your camera and burn a backup DVD of the images you just copied to your computer.

Using this process will save you a lot of hassle and problems if the battery happens to fail during your copying images from the camera to the computer

Http://keerok-photography.blogspot.com/2011/09/detailed-instructions-on-how-to.html

Why doesn't your way work already? USB technology isn't perfect yet. The camera is nothing more than a USB card reader when connected to the computer. You will want it that way. If the computer suddenly recognizes it as a camera, that's when all these troubles start.