I think the best thing to do is to call Canon and ask them. I have a flash that's broke which I need to call them about today too.

The last time I had a repair done on a camera cost $300 and all they replaced was a fractured piece of plastic on a D30. I wouldn't expect anything much less than that if there is in fact a hardware failure. If you're lucky, it's something really simple where no parts have to be replaced. Given them a call and see what they tell you. I've had other work done with them (replace shutter assembly on EOS-3 and aperture problems on a lens) and they are professionals.

Trevor