The dreaded E50 error

I've had my canon Powershot S400 for less than 4 years. Last week the memory refused to work and it refused to take a picture. This has happened before so I re-format the memory card and voila! It works again! However, this time the re-formatting function in the camera refused to work and the camera would shut itself down and say E50 on the screen and then the overwhelming sense of "the world is against me" sets in. This time I hooked Canon up to my less than 4 year old laptop that's already had it's hard drive replaced and through the WinXP camera wizard, took a picture with the camera using my computer keyboard. I felt like a dangerous hacker! And, I don't know why but it worked! My camera now works again! I don't have to give more money to Canon. So why doesn't my 20 year old toaster oven ever need to be re-formatted? You just turn it on and it puts a nice golden brown on everything (unless you forget and start doing something else). Also, can I control my toaster oven from my laptop? I bet one trip to Ace hardware and some speaker wire and a phone call to my brother @ the U would make it happen.