Hello Jack,
I’ve heard that you could try and do a full restart of your camera. Just take out BOTH batteries. There’s a date and time in the same slot as the main battery. You should be able to find it after a minute of sliding a finger on the sides. Check where the door hinge is. Once that’s done, remove the lens and CF card and have a cap put on, before leaving it for five to ten minutes. Capacitors inside may still have a charge, even after 20 seconds. Since I have a 20D that I’ve dropped, we’re in the same boat. I’ll try it and give you feedback once I have seen if it works. 20D’s are great cameras. If you are planning to get rid of it after you’ve had your satisfaction, give it as a gift to an aspiring photographer! I’ve had mine for a while now, and I’ve not have a problem with it until I dropped it. But, stay optimistic, I’m hoping as well.