40d issues

My 40d has started to play up. Whenever I go to take a photo, it will focus and confirm AF but when it goes to fire, the camera switches itself off. It seems like a problem with either the power or with the shutter.

Has anyone else experienced this problem? How did you remedy it?

I'm guessing that sending it in to a repair center will be expensive :S

Could be a bad battery. I assume you've made sure it's charged...

A battery could have enough juice for focusing but not enough to lift the mirror and operate the shutter.

For that matter, your charger could also be bad - telling you the battery is charged when it's not.

Trying another battery is much cheaper than a repair job. Check out Sterlingtek for quality batteries at good prices.

-js

Tried other batteries from friends and that didn't do it.

I've had the shutter replaced and that hasn't fixed the problem :S

Any more ideas?