I can't get the camera to turn back on. It powered off after I took a photo. I got home and charged the battery for 2 hours. The battery is fully charged and still the camera won't turn On.

SOURCE: My canon powershot sd950 is not turning on after I

I had the same problem. I sent it to Canon and it came back today fixed and free of charge even though I've had it for almost two years. Then I tried using it again tonight and it doesn't work again. I charged the battery pack, still not working. I found out that this camera has a service notice for it on canon's site. My camera does have one of the serial #'s they describe. I guess they fixed it for free b/c it was a loose screw but now it's come loose again the same day. How frustrating! I have to have a camera for tomorrow so I'll go buy another camera. I'll still send this one back to Canon and see what they do this time.
Here's the link so you can check your serial #. Good luck!
http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=224&modelid=15652&keycode=2112&id=55260

SOURCE: Canon PowerShot S45 Digital Camera

Maybe this fuse is blown:
http://www.hit-karlsruhe.de/aol2mime/images/S45_S50_PowerFuse.jpg
Short it or replace it.
See also http://www.hit-karlsruhe.de/aol2mime/canon_powershot.htm
Good luck!

SOURCE: Camera won't power up

Mine was the microswitch that tells the camera the battery / card door is closed. The tiny, cheap plastic protrusion that pushes on the switch broke off. Jam the switch with the end of a toothpick.

SOURCE: My Canon PowerShot SD950 IS won't turn on

Might want to take a look at this:
http://canoncanada.custhelp.com/app/answers/detail/a_id/11506/session/L3Nuby8xL3NpZC9FVFAyZDdCag==
My SD950 just refused to power on during a trip out west. Apparently a screw might have come out that prevents the camera from turning on. The repair is free-of-charge, even fro out-of-warranty period.
It is a beautiful camera: pictures are not too shabby, but the design is fantastic for a portable ...

SOURCE: Canon Powershot SD870 IS Digital Elph will not

This solution was originally posted by rulds2008.
"The battery regulator inside needs to be replaced around $15 from radioshack or you can take it to a camera shop for around $35 bucks. If its still under warrenty Take it in and have it repaired free."