Have you tried restoring the defaults through the menu system? It may be worth a try.
Normally real problems give an Error 99 report. I had shutter problems a few months back, and that the error report I got. It cost �162 to get it repaired!

The advice I got from Canon when I rang whem, was to remove the batteries, lens and card, and leave the camera for at least an hour. This sometimes clears any errors that may be in memory.

You could also try cleaning the contacts between the lens and camera with a soft pencil eraser, but be careful not to get any little bits inside the camera.

Hi-ho,

You can check to see if the AF module is working...

If you put the camera in single-shot focus mode, and select manual focus on the lens with just the center point selected, then point the camera at something really high contrast that it can't fail to detect.

As you manually focus with the shutter button half depressed the center focus point LED's in the viewfinder should light up the box as you pass through the 'in focus' point for your high contrast edge/line/subject.

If that dosn't work you might have a dead AF censor, or the sub-mirror is dirty.  Try all of the AF points seperately (remember only the center one is a 'cross' sensor) and if it's just one or two of them, the dirty submirror might be your problem.  Not too sure what you could do about that though, but a goot camera store may be able to help.

If it's all the points, it's a service... 

Cheers, Me.

sorry, guys. This is an old thread. It was the diopter.  Actually, it was the dumb**s user, but I'll blame it on the diopter.