My coolpix camera won't turn on, what can I do?

Battery is broken, replace the Nikon Coolpix 3100 Digital Camera Battery Bar: http://www.2deals.net/Digital-Camera-Battery/Nikon/Nikon-Coolpix-3100.html

I can only offer this: (sorry if it does not help)
When the micro USB Cable is plugged into the camera you MAY be able to take photos. The camera MAY work normally EXCEPT for the MONITOR or Screen. The screen is TURNED off when you plug in the cord.

10 replace batteries or recharged very well the batteries.
2) clean very well the contacts batteries from oxide, dust, dirty. or corrosion
3) batteries loaded in WRON direction
4) batteries is NOT the right type
5) poor contact between battery and cover , clean and adjust it .
6) Memory card slot/battery covert is open
God bless you

I had the same problem, and many other people have had this issue. The camera sat for too long, and the battery fully discharged. It needs to be reset. In order to do that, remove the battery and memory card. Replace only the battery, and plug it in. You should see a green light flashing to the right of the LCD screen. That means it is now charging. Replace your memory card, and let it charge before trying to use it.

Things to check first for a camera that won't turn on are battery contact points, and micro switches that are located on the battery and memory card doors. Troubleshooting tips on other things that need to be checked may be seen here. These tips won't work for every case, but they're worth a try.

Things to check first for a camera that won't turn on are battery contact points, and micro switches that are located on the battery and memory card doors. Troubleshooting tips on other things that need to be checked may be seen here. These tips won't work for every case, but they're worth a try.

Things to check first for a camera that won't turn on are battery contact points, and micro switches that are located on the battery and memory card doors. Troubleshooting tips on other things that need to be checked may be seen here. These tips won't work for every case, but they're worth a try.

Things to check first for a camera that won't turn on are battery contact points, and micro switches that are located on the battery and memory card doors. Troubleshooting tips on other things that need to be checked may be seen here. These tips won't work for every case, but they're worth a try.

You'll have to use a card reader. Despite the name, a card reader also lets you write to the card. Be aware that if the pictures were taken on a different type camera, or if you've done any editing on them, you probably won't be able to view them on the camera.

Consider NOT connecting your camera to your computer.
The best way to download pictures from your camera to your computer involves removing the memory card from the camera and plugging it into a card reader (either built-in to the computer or connected via USB or FireWire). This is likely to be faster than connecting the camera to the computer, and won't run down your camera's batteries.

Once the card is plugged in, it will appear to your computer as a removable drive. You can use the operating system's drag&drop facility to copy pictures from the card to the computer's hard drive, the same way you copy any other files. Or you can use any photo cataloging program, such as Nikon Transfer.