Our brand new Canon PowerShot A640 had exactly the same problem and it broke when my husband was in Portugal. Luckily it was still on warranty and Canon is fixing it for free and shipping it back within a week! Now I wonder if this is a regular problem with Canons.
It appears to be a problem with a Sony sensor which is common to many different makes of cameras. That link has a list, and it ranges from Canon to Konica to Fuji to Nikon.
I bought my Canon SD110 in April of 2005, so it's long out of warranty. I took it in and the lady behind the desk immediately recognized the symptoms and said they'd take it, ship it off to the Mainland, and get it back to me in 2 or 3 weeks, free of charge.
It sounds as if Murphy lives at your house.
I guess the more technical we get, the more problems can arise.
I hope all these broken items were under warranty.
could get expensive