If I'm in the sports mode on a Nikon D50 and it is shooting slow, what's wrong?

I'm shooting with a Nikon D50 and in the past when in Auto mode and I put it on the sports icon it used to shoot fast pictures and they would be crisp. Now when I shoot pictures in that setting it is blurry if the subject is moving.

That would mean that the shutter speed is low.increase the shutter speed to around 1/200 or more. If it gets too dark, Increase the ISO, or Decrease the Aperture value.

Modes are for those who haven't really learned how to operate a dslr. If you'd take time to learn the real functions of your camera you'd never even turn the wheel there - you'd do the settings yourself.

I suggest that a course, lots of reading and practice will get you there.

It means you don't have enough light. Perhaps your ISO is set too low.

You need to learn how ISO, shutter speed, and aperture interact.

Too dark or ISO too low. When shooting action, the easiest way to do it is to put the camera to Aperture-priority (A), set to lowest f/number, set ISO to 400 then do a test shot. If blurry, increase ISO bit by bit until satisfied. Take note that as ISO goes up picture grain becomes more evident. Also practice tracking your subject in motion and follow through even after you click the shutter button.