For that camera that died, here are some
non-intrusive simple fixes that you should try before throwing in the
towel. Copied this first post from somewhere. It was a fix for a Canon
A520, but am not sure if it would work for other cameras with the same
problem? For those of you with a camera that will not power up or turn
on, especially if this occurred after a power interruption with your
lens extended, please give it a try. If you do, please leave a comment
on specifics like your camera make/model, and whether it worked for you
or not."DEAD CAMERA, LENS OPEN-If the batteries run down completely while the camera is still open, it may not start up again when new batteries are installed. But if you remove the memory card, then install the new batteries, when you turn it on it should come back to life. Error E30 means you don't have a memory card installed, so turn it off, slip in the SD card and turn it on one last time."
OK, so the above didn't work. Next thing to look at are the batteries themselves. Are you using alkaline batteries, or worse yet those "Super Heavy Duty" batteries? If so, betcha we've just discovered your problem. Alkaline and regular "super heavy duty" batteries just don't have the power for more than a few pics in a digital camera. Some may even have problems just powering startup of the camera. It doesn't matter if they're new, and right out of the package. Digital cameras for the most part should only be used with rechargeable NiMH batteries (if you still have your instruction manual, open it to the "batteries" section. Pretty sure you'll see a statement similar to what I've just said). Most retailers sell NiMH batteries for around $7 for a package of four (about $15-19 for the batteries with charger). Keep in mind they'll save you big bucks in the long run over alkalines, AND they'll last for at least 100 pictures per charge (and probably many many more). You'll be very pleased with their performance, and may slap yourself for not buying them sooner. When at the store, look on the package for a power rating of at least 2500 mah.
OK, so maybe those newfangled batteries didn't fix your camera, don't give up just yet. The next thing to check is that your batteries are actually making contact with the battery posts, and that these posts are clean. If not, bend the posts up/down a little, and maybe clean them with a little rubbing alcohol on a Q-tip.
The next thing to try is examine both the battery and flash card door. There's usually a little switch on both doors (note some SD card doors do not have this switch) that activates when the doors are closed. If they don't, the camera won't start to prevent damage to the flash card or camera startup sequence. For most cameras its usually a little piece of plastic on the door that pushes in on a pin switch when the door is closed. Closely examine both doors to try to identify these switches. A lot of times that little plastic nib wears down or breaks off, but can easily be jury rigged with a small glued-on replacement.
Examples of Nibs and Pin Switches
If you've tried all of the above and still no luck, the problem is then likely to be internal to the camera. Am planning on posting sometime in the future some likely things to check, hopefully with a pictoral guide. One example would be that if your camera uses Compact Flash, check to make sure all pins are present and aligned in the card slot (if bent, simply unbend/straighten them with a skinny "jewelers" screwdriver, then insert the flash card for final realignment).
