I haven't turned the camera on for a couple of years. I've tried charging the battery, but I can't get it to power up. Do I need to replace battery or is it something else?

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

Hi, bring to your nearest service center to repair it.

Replace the battery.

the battery is probably bad

Mine wont turn on either, the battery is fully charged and inserted properly. I can tell this as the pre-flash light comes on but nothing else, the only way to get the pre-flash light off again is to remove the battery.

I have the same camera. It sounds to me that there is a fault with the camera itself and not the battery. You might be better sending Canon an email and asking them. My battery lasts forever so I would think if you already purchased another battery you've eliminated that problem. It might be the contacts inside the camera that are not accepting the full charge. Does the camera battery on screen show that it's full after you've charged it? Maybe trying charging it overnight and then trying it out the next day.

Are the batteries fully charged ?

I haven't done that on that product but i've changed only 1 of 2 batteries before. it does work for awhile but it would probably be best to change em all at once. If you do it this way they'll all be the same and you will be able to remember which ones are good and which ones are bad.

Based on what you've said here I would say that either the battery is incapable of maintaining a charge or something is draining the battery. To test to see if something is draining it, disconnect the positive cable and put an ameter between the cable and the battery to see what current is being 'used' when the ignition switch is off. It should read ZERO amps. If there is current flowing then something is draining the battery - pull fuses to find the culprit. If the drain shows ZERO amps then it's possible the battery is tired and needs to be replaced. Motorcycle batteries don't usually last more than a few years.

I hope this helped. Sorry for any typos.

Scott

Start with pulling the battery and power, then hold the power button in for about 30-40 seconds. Then plug the power back in (still no battery). Try to power up the computer. If it boots, shut it down and put the battery in and try again. If it boots the issue was cleared. If it boots with the power cord but not with the battery added, you have a battery issue.

Hope this helps