My 40d does not turn on, battery was fully charged, charger showed full light, put battery in, and camera does not turn on. Help!

Might be the camera's battery terminals, not the battery itself. Take a qtip and some isopropyl aclohol and clean the terminals in the battery well of camera.

Try charging it for an hour even if it is indicating that it is already full in 10 minutes. If the battery still gets drained after a few shots, then you should change your charger.

SOunds like your battery is bad. try discharing it :

1. Place the battery in your camera until it itself turns off. In this situation, the battery is fully discharged.
2. Take out your battery and slide it into your battery charger.
3. Connect your charger with power to fully charge the battery. It is normal for a new battery that battery indicator shows 100% capacity in 10 to 15 minutes. Please keep charging until there is no time left for charging.
4. Fully charged and fully discharged or "cycled" as much as five times to condition them into performing at full capacity.

Try it and see if it works? If the batteries are not rechargeable then the problem is in the cameras power supply and you need to take it in or replace it.

the charger light detect the battery level charge, shows red when charging and green when fully charged.when the charger light is not lit,may be the battery dosnt hold any charge that means its likely that the battery is defective

Advise you to buy a new Digital Camera Batteries for Canon PowerShot SD1100 IS
Replacement for: CANON NB-4L
,cheap and good performance.

It happened to me. I fixed it by luck . Here is my way . fully charge the camera till the led turns green. "IMPORTANT" unplug the power of the charger first, then remove the camera from the cradle . Then I pressed power button, it worked.
Wish good luck to you too
cz

Might seem obvious but check that the green light on the charging unit showed that the battery was fully charged before you put it in the camera. Make sure that the memory card is fully seated in the slot. If ok then either the charger is not charging or the on/off switch is faulty.

There are several different things that can cause the camera to not start up. Refer to your user manual to check each of these items. If you don't have your user manual, you can download it here.

1) The battery is not properly installed in the camera. (p.26)
2) Make sure the battery compartment cover is closed. (p.26)
3) Make sure the CF card slot cover is closed. (p.28)

In addition, the battery may not have been properly recharged. Double check that the charger is plugged into a working outlet, and double check that it shows that the battery is fully charged.

If none of these fix the problem then you have a defective camera - one of the switches for the battery compartment or the CF card slot cover may be not properly indicating that the door is closed. If that's the case, you need to either return it to the place of purchase as defective, or send it in to Canon for warranty repair.

Same problem. Fully charged main battery. In my case, I hadn't used the camera in over 6 months. All I did was pull the main battery and then pulled the small CR 2016 button cell battery located inside the main battery compartment and re-inserted both batteries. The camera made a quiet click and then turned on with the main power switch and asked to reset the date and time. Works fine now. If this doesn't work just purchase a new button cell.

Possible failed battery showing fully charged but actually not -or even charger.No reset] Disconnect from the wall socket- re connect and tell us if the battery is now charging. If show full- replace battery. Also tell Sony customer support