My Nikon D5000 is not letting me push the shutter down half way to foccus?

I have a Nikon D5000 and it has stopped focusing properly. When I take a picture I have to push the shutter down all the way and not just half way and get a beep telling me that the photo is going to be in focus. Can you help me please?

Added (1). Thanks for letting me know and yes it is under warranty thank goodness.

No we can't help you. You'll have to see a pro because the switch under the button has probably failed.
If it's under warranty contact Nikon… Otherwise, find a repair shop.

Double check that the lens is set to autofocus. The small switch on the lens may have accidentally been switched.