EOS T3i not taking photos

[Phillylady]

1. It turns on
2. The lower right green dot, as viewed through the eye viewer, flashes off and on when I press the shutter button.  Nothing happens beyond that.
3. The button will not go half way down to focus, and it will not click to take a photo.  Therefore it is not focusing, or taking a photo.
4. None of the other settings will take a photo either,
5. EXCEPT when I put it into video. It will record video and SNAP A PHOTO while I am in video.
6. I have removed the battery and reseated it three times, it is fully charged and I've also tried using a 2nd battery. This is not the problem.

7. I have removed the photo card and reseated it 3 times.  It has tons of memory room left on it. 
8. I have removed the lens twice, and wiped the contacts (which look pristine as I normally never remove the lens).  
9. The camera is definitely set to AF.

I'm trying to figure out if some other setting on the camera inadvertently got shifted, but for the life of me I can't figure out what that would be. I'm not adventurous with the camera and just use the bare basics.

At the time that this happened it suddenly showed reluctance, I had to press down several times to finally get it to snap two final photos, and then it suddenly locked up completely.  It hasn't been banged, or knocked around, so I am mystified.

If you have any suggestions it would be really helpful if you could put them into layman's terms.  Pretty please. 

[Phillylady]

IT'S FIXED!

Thanks to everybody who tried to help me with this.  It's taken me awhile to get back to this.

The auto-focus is now working and I wanted to explain why, so that anybody who reads this link in the future can see how I got to the end result.

1. I began to realize that, even in the manual focus position, my camera lens was not focusing. It wasn't focusing when I physically turned the lens at all.
2. It finally occured to me that it was the lens, and not the camera that having a problem.
3. Fortunately, I have a long distance lens that I rarely use, so I tried it out on the camera body instead.
4. The auto focus on the long distance lens worked just fine!

5. That proved the lens was the problem, and not the camera.
6. So today I went on line and typed in "EFS 18-55 lens auto focus not working".

7. It brought me to a different Cannon Community topic train of messages.
8. And this is what it said.
(Just to be accurate, in my case, followed the instruction given by Julio several times.  I did not hear any kind of a "Click" or "Snap", but when I put the lens back on the camera the auto-focus worked).

From Julio at Cannon:
"it does sound like it could be the motor in the lens. We have found that sometimes we're able to remedy this without a costly repair, but it is a multi-stepped process.

Try this:

1. Take the lens off of your camera.
2. Put the lens in MF mode.
3. Twist the FOCUS ring (the tip of the lens) all the way to one side (extend it). You may hear a click noise or two, this is good, but don't FORCE the lens.
4. Twist the FOCUS ring all the way to the opposite side (retract it). Again, you may hear a couple of clicking noises. What we hope is happening is the focusing motor being put back into its proper place.
5. Put the lens back on the camera.
6. Put the lens in AF mode.
7. Turn the camera on.
8. Put the camera in AUTO or P mode.
9. Take a test photo.
10. Profit.
    Hopefully this solves your problems, and you never have to worry about it again! With my personal lenses that are not USM or STM, I always store and transport them with the AF/MF switch in the MF position. This disengages the focusing motor and prevents any accidental damage to the auto focusing motor."