My canon zr400 wont turn on

Camera batteries do not last the lifetime of the camera. Its lifetime depends on usage and the number of times it's been charged. You may simply just need a new battery

Double check your battery to be sure that you bought the right kind. Also double check the reg/rec. This device is what is primarily responsible for the charging being correct. Overcharging should fall squarely on the shoulders of the reg/rec. if you didn't already replace it with a brand new part I'd still think that was the problem. If you did replace it, I suppose it is possible for your alternator to be broken and producing an absurd amount of energy, but I doubt it.

Two things: Are you absolutely sure the new batteries have a charge? Have you double checked to make sure they're in the correct direction...

It needs to go to Canon for service.There is a internal component failure

If you bought the camera in January, it's still under warranty for a year. When you get home call 1-800-OK-CANON to arrange warranty repair. They're usually very good about it, and will try to make things right.

You can download the software here.

http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&tabact=DownloadDetailTabAct&fcategoryid=326&modelid=11151

Good Luck and Please Rate FixYa!

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.

Just as a follow-up I managed to locate the problem. I opened the camcorder up as it is out of warranty anyways and found that there is a thin flat flexible cable which I will call a ribbon cable that is broken. It connects the main circuit board to the one that holds the external battery and internal battery. I have called Canon to purchase this part (it has a part number etched on it which when you read it off they say it sounds like a legitimate part number) and so far have not been able to get it (they assume it is part of the main circuit board assembly and have not been able to actually locate this part number). As it stands now I know the problem and can not get the part.

Camera will not power on. Canon posted a bulletin regarding a possible solution for some SD950's at the following website. Apparently this model has a screw that can come loose inside and the camera will not power. They just found this to be the case with my SD950, and they fixed it for free. It was outside of the warranty by a couple months. They even sent me a prepaid UPS shipping label to send them my camera for repair. See the link below for more on this possible solution:

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=224&modelid=15652&keycode=2112&id=55260

The battery is probably so dead it is using all the power from the wall supply.  Remove the battery, and run only from the wall supply.