Auto Focusing Stopped working

I own a Canon Rebel purchased in 2004. All of a sudden the autofocus stopped working and when the shutter button is depressed the autofocus keeps trying to focus and the flash strobes, but the picture cannot be snapped.

If the flash fires and it keeps trying to auto focus, it makes me think it can't find something to focus on or there is not enough light for the autofocus system to work properly.
To start, does another lens work ok? Did you or can you try another lens. What lens do you have?
Is the glass clean? If not, clean it.
The lens and body have electrical contacts on them. The camera and lens must be able to communicate with each other. Try cleaning them (the electrical contacts) with a pencil eraser.
Can you take a picture in the manual focus mode?
Is the focus ring jammed, or has the lens or camera been dropped?
A lot of things can cause this condition. These are the first and most obvious to eliminate.

I did try another lens, neither work and do the same thing. The shutter button does not click either to take a picture, due to all the other things going on - flash and focus... I can take pictures with the manual focus. I will try the focus ring and no the camera has never been dropped nor the lenses. I will try your recommendations tonite when I get home from work!
Thank you! I will post tomorrow the outcome.
So happy to have found this site! I am a pure amateur!

Hope it helps. Let us know.

I cleaned the contacts and the autofocus began working! I was elated - but then I now only get 1/4 of the picture showing the rest is black. Could this be the "plastic pin" problem Canon used in these cameras I have been hearing about? If so is it an easy fix and does it really have to be sent back to Canon? Thanks!

1/4 of the picture is black. If it's the top or bottom of the picture it may be the flash sync speed. Are you shooting in Program? Both lenses? If the problem happens with 2 lenses, the problem lies with the camera. One lens, it's usually the lens.
I have not heard about the plastic pin thing. Can't help there. Maybe someone else here is familiar with that.

For the most part I don't try to fix my cameras. I messed up too many already.

Sounds like you had a couple things going on there.

Thanks Jim,
I didn't try the other lens, why I don't know. I was quite excited when the AF started to work! I will try the other lens tonite. I would be more than happy to have to purchase a new lense, the one that I tried is the 18-55. So I will try the other! Thanks so much! I will let you know tonite!

I was shooting in Program.