My Camera is mocking me

We bought a Canon SD400 Digital ELPH camera about a year ago. We bought it from Best Buy, and also paid for the extended 4 year warranty. I figure the extra warranty is usually worth it for portable electronics.

Well, we were right to buy the warranty. Earlier this year, around April, the camera started to really act up. It wouldn't always turn on, it would turn off while trying to take a picture. It acted as if the battery were dead or dying, eventhough it had just been charged. I also have an extra battery, and the camera acts up, with whichever battery it is using.

The problems became worse when we went to Shanghai/Tokyo. The camera would only take pictures intermittently, and kept turning itself off.

About a month ago, I brought the camera, along with my warranty information to Best Buy. They looked up my warranty info, and said that yes, indeed, I was covered. I'm eligible for a new camera. I just had to show them how the camera wasn't working. Well, that's the trick, now isn't it? Of course, on this day, I stood at the counter for 30 minutes, taking pictures, and turning my camera off and on.

...and it worked just fine.

Soon afterwards, we went to Hawaii, and sure enough, it acted up again. This is becoming very frustrating.

This weekend, I brought the camera to Megan's Baby Shower, and it was back to it's old ways.
Last night, it was acting up while I was trying to take a picture of my dinner.

I have some time off this afternoon, so I figured, "Great! I'll bring my camera back into Best Buy to exchange it for a new one!"

Right before I was about to leave, I thought I'd better try it out to see if it was working or not.

(you can see this one coming, right?)

Yep, it's working perfectly again.

My camera is mocking me.
This is going to drive me crazy.