Canon can't lock focus

Your camera is a point and shoot. This means the camera does auto focus when you want to make a picture. The focus point is in the square in he middle of the screen. The only thing you can change is when you want to make macro pictures. The camera will try to find a focus point within 2 or 3 feet.
Ion some scenes, the focus will differ just a little, like in sports, it will try to be automatic.
The trick every professional photographer uses, is place the focus point on the part, you want to have in focus in your picture. Then press the shutter release button half and wait till the camera is in focus. Then reframe the picture as you want it to be. Then press the button fully. Just as described on page 31 of the manual.

There are several possible causes for blurry pictures.
1) Camera motion. If everything is blurry, it's most likely because the camera moved while the picture was being taken. Make sure your shutter speed is fast enough if you're handholding the camera (longer lenses require faster shutter speed). Alternatively, put your camera on a stable surface, such as a tripod or a tabletop.
2) Subject motion. If the subject is blurry but the background is sharper, then the subject may have moved while the picture was being taken. Use a faster shutter speed. Raise the ISO if needed. There are limits, of course. If you're trying to photograph a fast-moving object in the dark, you probably won't be able to.
3) Improper focus. If the subject is blurry but something else in the picture is sharp, then the camera probably focused on the wrong object. Move the focus selector to the subject you want in focus. Alternatively, center the viewfinder on the subject, press the shutter button halfway to lock focus, then reframe and shoot.
Without any more specific information as to what and how your pictures are blurry, I'm afraid the above is all I can give you.

Try resetting the Canon by removing the battery for 10 mins then insert the battery and set the Date and Time.

I could be that your lens isn't focusing. If the Auto focus can't find something to focus on the shutter won't fire. If you are shooting in low light sometimes it has trouble try shooting something that is well lit. also your auto focus point may be somewhere other than the center. there is a button on the top of your camera that looks like this [ ][ ] [ ] [ ]
More or less that will switch where your focus point is. If you look in the view finder and see a red dot when you push on the shutter button that is your focus point. push the above button until the red dot is in the centre. that may fix your problem.

There are several contributing factors to this problem and I'll try to list a few that may be the cause.
All Canon EOS camera auto focus modes us contrast to focus this means simply that no contrast there is no focus. There is a small green dot in the lower right corner of the viewfinder that will come on and stay on solid when auto focus as been achieved. By default the shutter will not operate "click" if auto focus has not been made.

Here are a few examples of where auto focus will ether search (focus back and forth) or fail completely.

A solid painted wall, glass between the camera and subject, mirror, chrome, any large body of water, clear sky. Another place you wouldn't expect is clear skin in your subjects face or body.

Cameras with multiple focus points and set to other then the middle will have a problem if the photographer is still attempting to use the center focus point.

Look for the green dot in the lower right corner of the viewfinder that's your focus confirmation.

TTTTTTTTTTTTTTTTTTTTTTTTITf correct focus cannot be obtained
When the subject to be focused is not on the AF target mark (not positioned
in the center of the composition), you can use the following steps to obtain the
correct focus on the subject. This operation is referred to as "focus lock".
Determine the position of the subject after focusing (Focus Lock)
1 Press the power switch.
• The camera turns on in the shooting
mode.
• The lens extends and the monitor turns
on.
• The orange lamp lights.
2 Turn the mode dial and select a
shooting mode.
"Shooting mode" (P.36)
3 Position the AF target mark on
the subject you want to focus on.
• When shooting a hard-to-focus
subject, point the camera at an object
about the same distance away as the
subject.
Press the shutter button halfway
until the green lamp lights.
• When the green lamp lights steadily,
the focus and the exposure are locked.
• When the green lamp blinks, the focus
and exposure are not locked. Release
your finger from the shutter button, reposition
your subject and press the
shutter button halfway again.
5 Keeping the shutter button
pressed halfway, recompose
your shot.
6 Press the shutter button fully.
Try the above, info from D-535, C-370 and X-450.
I can email you the complete manual if this works.
Regards
Phillip

to make the green square show up just press the shutter button until half (this is called the half press) when the green square shows up then it means that the camera has focused already, if not repeat the process til green square comes out you can press the shutter button fully to take picture when you see the green square...

There are two modes to the XS's Live View system, selectable via Custom Function 7. Live View is disabled by default, by the way, so you'll need to find this menu item in Settings Menu 2 to turn it on. The two options are called Quick and Live modes. Quick mode works as most Live View modes do, dropping the mirror when you press the AE-Lock button (marked with an asterisk) to use the conventional phase-detect autofocus system. This temporarily blacks out the Live View image, which makes it impossible to know that you're still framing the subject and holding your AF point in the proper place.
That's why they added the second mode, which they call Live, but is better described as contrast-detect autofocus. This works just like a digicam, reading the image from the imaging sensor while adjusting the lens for the setting that produces the most contrast in the image. A small square appears in the center of the image area, and you can move it around with the cross keys. Just like Quick mode, unfortunately, you have to press the AE-Lock button first until you hear the focus confirmation beep, then press the shutter button to fire. It's a little slower at times than phase-detect mode, but it gets the job done. Live mode is really better for tripod work, where you can place the AF area right where you want it and confirm focus onscreen.
Both modes offer the ability to zoom in on your live view, excellent for confirming focus before capture. Using the Magnify button just right of the AE-Lock button, you can zoom in 5x or 10x, then press the AE-Lock button to focus if you like; but of course you can't confirm framing in that mode.

You are expecting too much for any auto mode. When shooting under low light conditions, the camera may take longer to achieve focus lock. If the subject is moving too, it will take even longer to lock focus. Try using manual focus for the conditions you described.

You are expecting too much for any auto mode. When shooting under low light conditions, the camera may take longer to achieve focus lock. If the subject is moving too, it will take even longer to lock focus. Try using manual focus for the conditions you described.