The powershot a610 will not take pictures screen is blank. it will show previous pictures but nothing new

Have you tried pressing the display button 2 or three times?

It is ccd imager chip failure problem that need to be replaced.
Canon offers free of cost ccd imager chip replacement for same problem in many models, click Canon Support for details to get free of cost repair offer.
Thanks.

Either a "cracked" logic-board, or loose wires from the video-screen, so that nothing (except "darkness") is being sent from the photo-sensors to the logic-board.

Copy all the pictures from the card onto your PC, and then buy a new camera -- this will be less-expensive than having a camera-repair professional trouble-shoot it.

Camera needs service

A stuck shutter is another common failure mode for digital cameras. The symptoms of a stuck or "sticky" shutter are very similar to CCD image sensor failure. The camera may take black pictures (for shutter stuck closed), or the pictures may be very bright and overexposed, especially when taken outdoors (for shutter stuck open).
To confirm a stuck shutter, put the camera in any mode other than "Auto", and turn the flash OFF (you don't want to blind yourself for the next step). Next look down the lens and take a picture. You should see a tiny flicker in the center of the lens as the shutter opens and closes. If no movement is seen, then you likely have a stuck shutter. If so, please see this link for further info and a simple fix that may help:

probably ur sensor is dead or there is dirt and moisture accumulation over ur sensor.... it is a mechanical cover and the dirt-moisture ghlue is preventing it from opening and stimulating the sensor. take it to prf repairer and get the dirt removed.

i had the same problem with my POWERSHOT A610

Try the solution posted by frozen80 at http://www.fixya.com/support/t295396-canon_s2_black_screen. It fixed my Canon PowerShot A610 black screen (closed diaphragm) problem.

Much more likely that it's a stuck shutter, especially for your model camera. How many tries did you give the fix? Some people stated that it took at least 15 repeated tries before the shutter opened:
http://camerarepair.blogspot.com/2009/05/simple-fix-for-stuck-shutter.html

Believe that you accidentally pressed the DISP button on the bottom back row of your camera. This manually turns the display on and off as desired to save batteries. Press the button once more to turn it back on.

I have the same problem and very frustrating! The camera turns on by won't show anything (totally black) in the camera mode. The menu still works. If I take a picture the display is black and shows black for it in the display mode model as well. Tried everything that I can think of but nothing helped. (Taking out the batteries and reinstalling, switching the mode from display to camera and back, stepping through each mode option, stepping through each menu options). The last option worked once but won't work later on. From this forum this seems to be a common problem with this camera. Guess won't buy another camera from Canon any more. I bought a camera (non-digitals SLR) from Canon before and was very happy with it for over 20 years. Thought Canon had the right thing in camera. This problem made me think twice when I buy another camera in the future. Perhap Canon is not as good as I thought. By not fixing the known problem, they are ruining their reputation.